Add calls to EnsureGPUMemoryAvailable into GLES2DecoderImpl

gpu/command_buffer/service/renderbuffer_manager.cc

Index: gpu/command_buffer/service/renderbuffer_manager.cc
diff --git a/gpu/command_buffer/service/renderbuffer_manager.cc b/gpu/command_buffer/service/renderbuffer_manager.cc
index e842de14ac4befba972f10d4d6da88bd856c7305..0c9e480efab7260476f263cc7f1ed73a50eb266f 100644
--- a/gpu/command_buffer/service/renderbuffer_manager.cc
+++ b/gpu/command_buffer/service/renderbuffer_manager.cc
@@ -36,8 +36,10 @@ RenderbufferManager::~RenderbufferManager() {
 }
 
 size_t RenderbufferManager::RenderbufferInfo::EstimatedSize() {
-  return width_ * height_ * samples_ *
-         GLES2Util::RenderbufferBytesPerPixel(internal_format_);
+  uint32 size = 0;
+  GLES2Util::ComputeEstimatedRenderbufferSize(
+      width_, height_, samples_, internal_format_, &size);
+  return size;
 }
 
 void RenderbufferManager::RenderbufferInfo::AddToSignature(