diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 95c5e61..072a8ce 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -1417,7 +1417,10 @@
                 ioFormat.fColorType = GrColorType::kBGRA_8888;
                 ioFormat.fExternalType = GR_GL_UNSIGNED_BYTE;
                 ioFormat.fExternalTexImageFormat = 0;  // TODO: Enable this on non-ES GL
-                ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_BGRA : 0;
+                ioFormat.fExternalReadFormat =
+                        formatWorkarounds.fDisallowBGRA8ReadPixels ? 0 : GR_GL_BGRA;
+                // Not guaranteed by ES/WebGL.
+                ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
             }
         }
 
@@ -1439,7 +1442,10 @@
                 ioFormat.fColorType = GrColorType::kBGRA_8888;
                 ioFormat.fExternalType = GR_GL_UNSIGNED_BYTE;
                 ioFormat.fExternalTexImageFormat = GR_GL_BGRA;
-                ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_BGRA : 0;
+                ioFormat.fExternalReadFormat =
+                        formatWorkarounds.fDisallowBGRA8ReadPixels ? 0 : GR_GL_BGRA;
+                // Not guaranteed by ES/WebGL.
+                ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
             }
 
             // Format: RGBA8, Surface: kBGRA_8888, Data: kRGBA_8888
@@ -1529,7 +1535,9 @@
                     ioFormat.fColorType = GrColorType::kAlpha_8;
                     ioFormat.fExternalType = GR_GL_UNSIGNED_BYTE;
                     ioFormat.fExternalTexImageFormat = GR_GL_RED;
-                    ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_RED : 0;
+                    ioFormat.fExternalReadFormat = GR_GL_RED;
+                    // Not guaranteed by ES/WebGL.
+                    ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                 }
 
                 // Format: R8, Surface: kAlpha_8, Data: kAlpha_8xxx
@@ -1561,7 +1569,9 @@
                     ioFormat.fColorType = GrColorType::kGray_8;
                     ioFormat.fExternalType = GR_GL_UNSIGNED_BYTE;
                     ioFormat.fExternalTexImageFormat = GR_GL_RED;
-                    ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_RED : 0;
+                    ioFormat.fExternalReadFormat = GR_GL_RED;
+                    // Not guaranteed by ES/WebGL.
+                    ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                 }
 
                 // Format: R8, Surface: kGray_8, Data: kGray_8xxx
@@ -1655,7 +1665,9 @@
                         ioFormat.fColorType = GrColorType::kAlpha_8;
                         ioFormat.fExternalType = GR_GL_UNSIGNED_BYTE;
                         ioFormat.fExternalTexImageFormat = GR_GL_ALPHA;
-                        ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_ALPHA : 0;
+                        ioFormat.fExternalReadFormat = GR_GL_ALPHA;
+                        // Not guaranteed by ES/WebGL.
+                        ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                     }
 
                     // Format: ALPHA8, Surface: kAlpha_8, Data: kRGBA_8888
@@ -1863,7 +1875,10 @@
                     ioFormat.fExternalType = GR_GL_UNSIGNED_BYTE;
                     ioFormat.fExternalTexImageFormat = GR_GL_BGRA;
                     ioFormat.fExternalReadFormat = 0;
-                    ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_BGRA : 0;
+                    ioFormat.fExternalReadFormat =
+                            formatWorkarounds.fDisallowBGRA8ReadPixels ? 0 : GR_GL_BGRA;
+                    // Not guaranteed by ES/WebGL.
+                    ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                 }
 
                 // Format: BGRA8, Surface: kBGRA_8888, Data: kRGBA_8888
@@ -1933,7 +1948,9 @@
                     ioFormat.fColorType = GrColorType::kBGR_565;
                     ioFormat.fExternalType = GR_GL_UNSIGNED_SHORT_5_6_5;
                     ioFormat.fExternalTexImageFormat = GR_GL_RGB;
-                    ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_RGB : 0;
+                    ioFormat.fExternalReadFormat = GR_GL_RGB;
+                    // Not guaranteed by ES/WebGL.
+                    ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                 }
 
                 // Format: RGB565, Surface: kBGR_565, Data: kRGBA_8888
@@ -2037,7 +2054,9 @@
                     ioFormat.fColorType = GrColorType::kRGBA_F16;
                     ioFormat.fExternalType = halfFloatType;
                     ioFormat.fExternalTexImageFormat = GR_GL_RGBA;
-                    ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_RGBA : 0;
+                    ioFormat.fExternalReadFormat = GR_GL_RGBA;
+                    // Not guaranteed by ES/WebGL.
+                    ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                 }
 
                 // Format: RGBA16F, Surface: kRGBA_F16, Data: kRGBA_F32
@@ -2068,7 +2087,9 @@
                     ioFormat.fColorType = GrColorType::kRGBA_F16_Clamped;
                     ioFormat.fExternalType = halfFloatType;
                     ioFormat.fExternalTexImageFormat = GR_GL_RGBA;
-                    ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_RGBA : 0;
+                    ioFormat.fExternalReadFormat = GR_GL_RGBA;
+                    // Not guaranteed by ES/WebGL.
+                    ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                 }
 
                 // Format: RGBA16F, Surface: kRGBA_F16_Clamped, Data: kRGBA_F32
@@ -2158,7 +2179,9 @@
                     ioFormat.fColorType = GrColorType::kAlpha_F16;
                     ioFormat.fExternalType = halfFloatType;
                     ioFormat.fExternalTexImageFormat = GR_GL_RED;
-                    ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_RED : 0;
+                    ioFormat.fExternalReadFormat = GR_GL_RED;
+                    // Not guaranteed by ES/WebGL.
+                    ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                 }
 
                 // Format: R16F, Surface: kAlpha_F16, Data: kAlpha_F32xxx
@@ -2453,7 +2476,9 @@
                     ioFormat.fColorType = GrColorType::kRGBA_1010102;
                     ioFormat.fExternalType = GR_GL_UNSIGNED_INT_2_10_10_10_REV;
                     ioFormat.fExternalTexImageFormat = GR_GL_RGBA;
-                    ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_RGBA : 0;
+                    ioFormat.fExternalReadFormat = GR_GL_RGBA;
+                    // Not guaranteed by ES/WebGL.
+                    ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                 }
 
                 // Format: RGB10_A2, Surface: kRGBA_1010102, Data: kRGBA_8888
@@ -2516,7 +2541,9 @@
                 ioFormat.fColorType = GrColorType::kABGR_4444;
                 ioFormat.fExternalType = GR_GL_UNSIGNED_SHORT_4_4_4_4;
                 ioFormat.fExternalTexImageFormat = GR_GL_RGBA;
-                ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_RGBA : 0;
+                ioFormat.fExternalReadFormat = GR_GL_RGBA;
+                // Not guaranteed by ES/WebGL.
+                ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
             }
 
             // Format: RGBA4, Surface: kABGR_4444, Data: kRGBA_8888
@@ -2753,7 +2780,9 @@
                     ioFormat.fColorType = GrColorType::kAlpha_16;
                     ioFormat.fExternalType = GR_GL_UNSIGNED_SHORT;
                     ioFormat.fExternalTexImageFormat = GR_GL_RED;
-                    ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_RED : 0;
+                    ioFormat.fExternalReadFormat = GR_GL_RED;
+                    // Not guaranteed by ES/WebGL.
+                    ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                 }
 
                 // Format: R16, Surface: kAlpha_16, Data: kAlpha_8xxx
@@ -2820,7 +2849,9 @@
                     ioFormat.fColorType = GrColorType::kRG_1616;
                     ioFormat.fExternalType = GR_GL_UNSIGNED_SHORT;
                     ioFormat.fExternalTexImageFormat = GR_GL_RG;
-                    ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_RG : 0;
+                    ioFormat.fExternalReadFormat = GR_GL_RG;
+                    // Not guaranteed by ES/WebGL.
+                    ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                 }
 
                 // Format: GR_GL_RG16, Surface: kRG_1616, Data: kRGBA_8888
@@ -2886,7 +2917,9 @@
                     ioFormat.fColorType = GrColorType::kRGBA_16161616;
                     ioFormat.fExternalType = GR_GL_UNSIGNED_SHORT;
                     ioFormat.fExternalTexImageFormat = GR_GL_RGBA;
-                    ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_RGBA : 0;
+                    ioFormat.fExternalReadFormat = GR_GL_RGBA;
+                    // Not guaranteed by ES/WebGL.
+                    ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                 }
 
                 // Format: GR_GL_RGBA16, Surface: kRGBA_16161616, Data: kRGBA_8888
@@ -2976,7 +3009,9 @@
                     ioFormat.fColorType = GrColorType::kRG_F16;
                     ioFormat.fExternalType = halfFloatType;
                     ioFormat.fExternalTexImageFormat = GR_GL_RG;
-                    ioFormat.fExternalReadFormat = GR_IS_GR_GL(standard) ? GR_GL_RG : 0;
+                    ioFormat.fExternalReadFormat = GR_GL_RG;
+                    // Not guaranteed by ES/WebGL.
+                    ioFormat.fRequiresImplementationReadQuery = !GR_IS_GR_GL(standard);
                 }
 
                 // Format: GR_GL_RG16F, Surface: kRG_F16, Data: kRGBA_F32
@@ -3847,6 +3882,10 @@
         // http://skbug.com/8921
         shaderCaps->fCanOnlyUseSampleMaskWithStencil = true;
     }
+
+    if (ctxInfo.angleBackend() == GrGLANGLEBackend::kD3D9) {
+        formatWorkarounds->fDisallowBGRA8ReadPixels = true;
+    }
 }
 
 void GrGLCaps::onApplyOptionsOverrides(const GrContextOptions& options) {
@@ -3962,15 +4001,18 @@
             for (int j = 0; j < ctInfo.fExternalIOFormatCount; ++j) {
                 const auto& ioInfo = ctInfo.fExternalIOFormats[j];
                 if (ioInfo.fExternalReadFormat != 0) {
-                    GrGLenum transferOffsetAlignment =
-                            offset_alignment_for_transfer_buffer(ioInfo.fExternalType);
-                    if (ioInfo.fColorType == dstColorType) {
-                        return {dstColorType, transferOffsetAlignment};
-                    }
-                    // Currently we just pick the first supported format that we find as our
-                    // fallback.
-                    if (fallbackRead.fColorType == GrColorType::kUnknown) {
-                        fallbackRead = {ioInfo.fColorType, transferOffsetAlignment};
+                    if (formatInfo.fHaveQueriedImplementationReadSupport ||
+                        !ioInfo.fRequiresImplementationReadQuery) {
+                        GrGLenum transferOffsetAlignment =
+                                offset_alignment_for_transfer_buffer(ioInfo.fExternalType);
+                        if (ioInfo.fColorType == dstColorType) {
+                            return {dstColorType, transferOffsetAlignment};
+                        }
+                        // Currently we just pick the first supported format that we find as our
+                        // fallback.
+                        if (fallbackRead.fColorType == GrColorType::kUnknown) {
+                            fallbackRead = {ioInfo.fColorType, transferOffsetAlignment};
+                        }
                     }
                 }
             }
@@ -4134,6 +4176,48 @@
     return SkToBool(this->getFormatInfo(format).fFlags & FormatInfo::kUseTexStorage_Flag);
 }
 
+bool GrGLCaps::shouldQueryImplementationReadSupport(GrGLFormat format) const {
+    const auto& formatInfo = const_cast<GrGLCaps*>(this)->getFormatInfo(format);
+    if (!formatInfo.fHaveQueriedImplementationReadSupport) {
+        // Check whether we will actually learn anything useful.
+        bool needQuery = false;
+        for (int i = 0; i < formatInfo.fColorTypeInfoCount && !needQuery; ++i) {
+            const auto& surfCTInfo = formatInfo.fColorTypeInfos[i];
+            for (int j = 0; j < surfCTInfo.fExternalIOFormatCount; ++j) {
+                if (surfCTInfo.fExternalIOFormats[j].fRequiresImplementationReadQuery) {
+                    needQuery = true;
+                    break;
+                }
+            }
+        }
+        if (!needQuery) {
+            // Pretend we already checked it.
+            const_cast<FormatInfo&>(formatInfo).fHaveQueriedImplementationReadSupport = true;
+        }
+    }
+    return !formatInfo.fHaveQueriedImplementationReadSupport;
+}
+
+void GrGLCaps::didQueryImplementationReadSupport(GrGLFormat format,
+                                                 GrGLenum readFormat,
+                                                 GrGLenum readType) const {
+    auto& formatInfo = const_cast<GrGLCaps*>(this)->getFormatInfo(format);
+    for (int i = 0; i < formatInfo.fColorTypeInfoCount; ++i) {
+        auto& surfCTInfo = formatInfo.fColorTypeInfos[i];
+        for (int j = 0; j < surfCTInfo.fExternalIOFormatCount; ++j) {
+            auto& readCTInfo = surfCTInfo.fExternalIOFormats[j];
+            if (readCTInfo.fRequiresImplementationReadQuery) {
+                if (readCTInfo.fExternalReadFormat != readFormat ||
+                    readCTInfo.fExternalType != readType) {
+                    // Don't zero out fExternalType. It's also used for writing data to the texture!
+                    readCTInfo.fExternalReadFormat = 0;
+                }
+            }
+        }
+    }
+    formatInfo.fHaveQueriedImplementationReadSupport = true;
+}
+
 bool GrGLCaps::onAreColorTypeAndFormatCompatible(GrColorType ct,
                                                  const GrBackendFormat& format) const {
     GrGLFormat glFormat = format.asGLFormat();
diff --git a/src/gpu/gl/GrGLCaps.h b/src/gpu/gl/GrGLCaps.h
index 59818dd..0e87ba1 100644
--- a/src/gpu/gl/GrGLCaps.h
+++ b/src/gpu/gl/GrGLCaps.h
@@ -199,6 +199,20 @@
     bool formatSupportsTexStorage(GrGLFormat) const;
 
     /**
+     * Would it be useful to check GL_IMPLEMENTATION_READ_FORMAT and _TYPE for this format to
+     * detect more efficient glReadPixels arguments?
+     */
+    bool shouldQueryImplementationReadSupport(GrGLFormat format) const;
+
+    /**
+     * Let caps know the result of GL_IMPLEMENTATION_READ_FORMAT and _TYPE query for a format
+     * to update supported glReadPixels arguments.
+     */
+    void didQueryImplementationReadSupport(GrGLFormat format,
+                                           GrGLenum readFormat,
+                                           GrGLenum readType) const;
+
+    /**
      * Gets the internal format to use with glRenderbufferStorageMultisample...(). May be sized or
      * base depending upon the GL. Not applicable to compressed textures.
      */
@@ -463,6 +477,7 @@
         bool fDisableLuminance16F = false;
         bool fDontDisableTexStorageOnAndroid = false;
         bool fDisallowDirectRG8ReadPixels = false;
+        bool fDisallowBGRA8ReadPixels = false;
     };
 
     void applyDriverCorrectnessWorkarounds(const GrGLContextInfo&, const GrContextOptions&,
@@ -583,15 +598,25 @@
             GrGLenum fExternalType = 0;
             GrGLenum fExternalTexImageFormat = 0;
             GrGLenum fExternalReadFormat = 0;
+            /**
+             * Must check whether GL_IMPLEMENTATION_COLOR_READ_FORMAT and _TYPE match
+             * fExternalReadFormat and fExternalType before using with glReadPixels.
+             */
+            bool fRequiresImplementationReadQuery = false;
         };
 
-        GrGLenum externalFormat(GrColorType externalColorType, ExternalFormatUsage usage) const {
+        GrGLenum externalFormat(GrColorType externalColorType, ExternalFormatUsage usage,
+                                bool haveQueriedImplementationReadFormat) const {
             for (int i = 0; i < fExternalIOFormatCount; ++i) {
                 if (fExternalIOFormats[i].fColorType == externalColorType) {
                     if (usage == kTexImage_ExternalFormatUsage) {
                         return fExternalIOFormats[i].fExternalTexImageFormat;
                     } else {
                         SkASSERT(usage == kReadPixels_ExternalFormatUsage);
+                        if (!haveQueriedImplementationReadFormat &&
+                            fExternalIOFormats[i].fRequiresImplementationReadQuery) {
+                            return 0;
+                        }
                         return fExternalIOFormats[i].fExternalReadFormat;
                     }
                 }
@@ -626,7 +651,8 @@
                                 ExternalFormatUsage usage) const {
             for (int i = 0; i < fColorTypeInfoCount; ++i) {
                 if (fColorTypeInfos[i].fColorType == surfaceColorType) {
-                    return fColorTypeInfos[i].externalFormat(externalColorType, usage);
+                    return fColorTypeInfos[i].externalFormat(externalColorType, usage,
+                                                             fHaveQueriedImplementationReadSupport);
                 }
             }
             return 0;
@@ -676,6 +702,8 @@
         // This value is only valid for regular formats. Compressed formats will be 0.
         GrGLenum fBytesPerPixel = 0;
 
+        bool fHaveQueriedImplementationReadSupport = false;
+
         enum {
             // This indicates that a stencil format has not yet been determined for the config.
             kUnknown_StencilIndex = -1,
diff --git a/src/gpu/gl/GrGLGpu.cpp b/src/gpu/gl/GrGLGpu.cpp
index 313aaef..f797b6c 100644
--- a/src/gpu/gl/GrGLGpu.cpp
+++ b/src/gpu/gl/GrGLGpu.cpp
@@ -2302,6 +2302,14 @@
     if (this->glCaps().srgbWriteControl()) {
         this->flushFramebufferSRGB(this->caps()->isFormatSRGB(target->backendFormat()));
     }
+
+    if (this->glCaps().shouldQueryImplementationReadSupport(target->format())) {
+        GrGLint format;
+        GrGLint type;
+        GR_GL_GetIntegerv(this->glInterface(), GR_GL_IMPLEMENTATION_COLOR_READ_FORMAT, &format);
+        GR_GL_GetIntegerv(this->glInterface(), GR_GL_IMPLEMENTATION_COLOR_READ_TYPE, &type);
+        this->glCaps().didQueryImplementationReadSupport(target->format(), format, type);
+    }
 }
 
 void GrGLGpu::flushFramebufferSRGB(bool enable) {