Rename SkFontHost_win_dw.cpp SkScalerContext.

This is a continuation of https://codereview.chromium.org/314193002/ .

TBR=reed@google.com

Review URL: https://codereview.chromium.org/315173004
diff --git a/gyp/ports.gyp b/gyp/ports.gyp
index afc446c..ea38ba8 100644
--- a/gyp/ports.gyp
+++ b/gyp/ports.gyp
@@ -34,11 +34,11 @@
         '../src/fonts/SkFontMgr_indirect.cpp',
         '../src/fonts/SkRemotableFontMgr.cpp',
         '../src/ports/SkFontHost_win.cpp',
-        '../src/ports/SkFontHost_win_dw.cpp',
         '../src/ports/SkFontMgr_default_gdi.cpp',
         '../src/ports/SkFontMgr_default_dw.cpp',
         '../src/ports/SkFontMgr_win_dw.cpp',
         '../src/ports/SkRemotableFontMgr_win_dw.cpp',
+        '../src/ports/SkScalerContext_win_dw.cpp',
         '../src/ports/SkScalerContext_win_dw.h',
         '../src/ports/SkTypeface_win_dw.cpp',
         '../src/ports/SkTypeface_win_dw.h',
@@ -163,7 +163,6 @@
           'sources!': [
             '../src/ports/SkDebug_win.cpp',
             '../src/ports/SkFontHost_win.cpp',
-            '../src/ports/SkFontHost_win_dw.cpp',
             '../src/ports/SkFontMgr_default_gdi.cpp',
             '../src/ports/SkFontMgr_default_dw.cpp',
             '../src/ports/SkFontMgr_win_dw.cpp',
@@ -171,6 +170,7 @@
             '../src/ports/SkRemotableFontMgr_win_dw.cpp',
             '../src/ports/SkTime_win.cpp',
             '../src/ports/SkTLS_win.cpp',
+            '../src/ports/SkScalerContext_win_dw.cpp',
             '../src/ports/SkScalerContext_win_dw.h',
             '../src/ports/SkTypeface_win_dw.cpp',
             '../src/ports/SkTypeface_win_dw.h',
diff --git a/src/ports/SkFontHost_win_dw.cpp b/src/ports/SkScalerContext_win_dw.cpp
similarity index 100%
rename from src/ports/SkFontHost_win_dw.cpp
rename to src/ports/SkScalerContext_win_dw.cpp