Migrate WebGL contexts on backgrounded tabs to the integrated GPU.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index c4470e8163b9bcad02becb46d5487236d218cb2c..11e1fc76d7923499d60904a39ed9cde87ce02bb4 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -1865,6 +1865,9 @@ class GLES2DecoderImpl : public GLES2Decoder, public ErrorStateClient {
   void DoPushGroupMarkerEXT(GLsizei length, const GLchar* group);
   void DoPopGroupMarkerEXT(void);
 
+  // Wrapper for PerformanceHintCHROMIUM.
+  void DoPerformanceHintCHROMIUM(GLenum mode);
+
   // Gets the number of values that will be returned by glGetXXX. Returns
   // false if pname is unknown.
   bool GetNumValuesReturnedForGLGet(GLenum pname, GLsizei* num_values);
@@ -19132,6 +19135,20 @@ void GLES2DecoderImpl::RestoreAllExternalTextureBindingsIfNeeded() {
       texture_manager()->GetServiceIdGeneration();
 }
 
+void GLES2DecoderImpl::DoPerformanceHintCHROMIUM(GLenum mode) {
+  switch (mode) {
+    case GL_LOW_POWER_CHROMIUM:
+      context_->SetPerformancePreference(gl::PreferLowPower);
+      break;
+    case GL_DEFAULT_POWER_CHROMIUM:
+      context_->SetPerformancePreference(gl::PreferDefaultPerformance);
+      break;
+    case GL_HIGH_PERFORMANCE_CHROMIUM:
+      context_->SetPerformancePreference(gl::PreferHighPerformance);
+      break;
+  }
+}
+
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.