Add ANGLE workaround to prefer flushes over VRAM usage

src/gpu/gl/GrGLCaps.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrGLCaps.h"
 
@@ skipping 453 matching lines @@
     if (kPowerVR54x_GrGLRenderer == ctxInfo.renderer() ||
         kPowerVRRogue_GrGLRenderer == ctxInfo.renderer() ||
         kAdreno3xx_GrGLRenderer == ctxInfo.renderer()) {
         fUseDrawInsteadOfClear = true;
     }
 
     if (kAdreno4xx_GrGLRenderer == ctxInfo.renderer()) {
         fUseDrawInsteadOfPartialRenderTargetWrite = true;
     }
 
+#ifdef SK_BUILD_FOR_WIN
+    // On ANGLE deferring flushes can lead to GPU starvation
+    fPreferVRAMUseOverFlushes = !isANGLE;
+#endif
+
     if (kChromium_GrGLDriver == ctxInfo.driver()) {
         fMustClearUploadedBufferData = true;
     }
 
     if (kGL_GrGLStandard == standard) {
         // ARB allows mixed size FBO attachments, EXT does not.
         if (ctxInfo.version() >= GR_GL_VER(3, 0) ||
             ctxInfo.hasExtension("GL_ARB_framebuffer_object")) {
             fOversizedStencilSupport = true;
         } else {
@@ skipping 656 matching lines @@
     r.appendf("Fragment coord conventions support: %s\n",
              (fFragCoordsConventionSupport ? "YES": "NO"));
     r.appendf("Vertex array object support: %s\n", (fVertexArrayObjectSupport ? "YES": "NO"));
     r.appendf("Instanced drawing support: %s\n", (fInstancedDrawingSupport ? "YES": "NO"));
     r.appendf("Direct state access support: %s\n", (fDirectStateAccessSupport ? "YES": "NO"));
     r.appendf("Debug support: %s\n", (fDebugSupport ? "YES": "NO"));
     r.appendf("Multisample disable support: %s\n", (fMultisampleDisableSupport ? "YES" : "NO"));
     r.appendf("Use non-VBO for dynamic data: %s\n",
              (fUseNonVBOVertexAndIndexDynamicData ? "YES" : "NO"));
     r.appendf("SRGB write contol: %s\n", (fSRGBWriteControl ? "YES" : "NO"));
-    r.appendf("RGBA 8888 pixel ops are slow: %s\n", (fRGBA8888PixelsOpsAreSlow? "YES" : "NO"));
-    r.appendf("Partial FBO read is slow: %s\n", (fPartialFBOReadIsSlow? "YES" : "NO"));
+    r.appendf("RGBA 8888 pixel ops are slow: %s\n", (fRGBA8888PixelsOpsAreSlow ? "YES" : "NO"));
+    r.appendf("Partial FBO read is slow: %s\n", (fPartialFBOReadIsSlow ? "YES" : "NO"));
     return r;
 }
 
 static GrGLenum precision_to_gl_float_type(GrSLPrecision p) {
     switch (p) {
     case kLow_GrSLPrecision:
         return GR_GL_LOW_FLOAT;
     case kMedium_GrSLPrecision:
         return GR_GL_MEDIUM_FLOAT;
     case kHigh_GrSLPrecision:
@@ skipping 70 matching lines @@
         for (int p = 0; p < kGrSLPrecisionCount; ++p) {
             glslCaps->fFloatPrecisions[kGeometry_GrShaderType][p] = 
                                                glslCaps->fFloatPrecisions[kVertex_GrShaderType][p];
         }
     }
 }