Move GrSurfaceContext.h and GrTextureContext.h to src/gpu from include/gpu

Change-Id: I5b68650d2417018e217a2fef2f852316ebd9de6f
Reviewed-on: https://skia-review.googlesource.com/9637
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

gn/gpu.gni

@@ -29,9 +29,7 @@ skia_gpu_sources = [
   "$_include/gpu/GrShaderCaps.h",
   "$_include/gpu/GrShaderVar.h",
   "$_include/gpu/GrSurface.h",
-  "$_include/gpu/GrSurfaceContext.h",
   "$_include/gpu/GrTexture.h",
-  "$_include/gpu/GrTextureContext.h",
   "$_include/gpu/GrSamplerParams.h",
   "$_include/gpu/GrTestUtils.h",
   "$_include/gpu/GrTypes.h",
@@ -201,11 +199,13 @@ skia_gpu_sources = [
   "$_src/gpu/GrSurfacePriv.h",
   "$_src/gpu/GrSurface.cpp",
   "$_src/gpu/GrSurfaceContext.cpp",
+  "$_src/gpu/GrSurfaceContext.h",
   "$_src/gpu/GrSurfaceProxy.cpp",
   "$_src/gpu/GrTexture.cpp",
   "$_src/gpu/GrTextureAdjuster.cpp",
   "$_src/gpu/GrTextureAdjuster.h",
   "$_src/gpu/GrTextureContext.cpp",
+  "$_src/gpu/GrTextureContext.h",
   "$_src/gpu/GrTextureMaker.cpp",
   "$_src/gpu/GrTextureMaker.h",
   "$_src/gpu/GrTexturePriv.h",