WebGL: Tidy up buffer allocation logic

gpu/command_buffer/common/gpu_memory_buffer_support.h

Index: gpu/command_buffer/common/gpu_memory_buffer_support.h
diff --git a/gpu/command_buffer/common/gpu_memory_buffer_support.h b/gpu/command_buffer/common/gpu_memory_buffer_support.h
index aa8c567dee0d4092f169810fe746b6d88e80a248..9f1dfbd42f1e9d1826657ea6f57f0ccbebfa0c05 100644
--- a/gpu/command_buffer/common/gpu_memory_buffer_support.h
+++ b/gpu/command_buffer/common/gpu_memory_buffer_support.h
@@ -14,11 +14,6 @@ namespace gpu {
 
 struct Capabilities;
 
-// Returns a valid GpuMemoryBuffer format given a valid internalformat as
-// defined by CHROMIUM_image.
-GPU_EXPORT gfx::BufferFormat DefaultBufferFormatForImageFormat(
-    unsigned internalformat);
-
 // Returns true if |internalformat| is compatible with |format|.
 GPU_EXPORT bool IsImageFormatCompatibleWithGpuMemoryBufferFormat(
     unsigned internalformat,