Address comments from zmo on an earlier CL.

Address zmo's comments on the earlier change:
https://chromium-review.googlesource.com/1885636
which were published after the CL landed.

Bug: 681341
Change-Id: Ib89967cc4f6b7f11371e7694689445d8afc34883
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1977739
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Auto-Submit: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#726997}

content/browser/gpu/gpu_data_manager_impl_private.cc

@@ -879,7 +879,15 @@ void GpuDataManagerImplPrivate::HandleGpuSwitch() {
 bool GpuDataManagerImplPrivate::UpdateActiveGpu(uint32_t vendor_id,
                                                 uint32_t device_id) {
   // Heuristics for dual-GPU detection.
+#if defined(OS_WIN)
+  // On Windows, "Microsoft Basic Render Driver" now shows up as a
+  // secondary GPU.
+  bool is_dual_gpu = gpu_info_.secondary_gpus.size() == 2;
+#else
   bool is_dual_gpu = gpu_info_.secondary_gpus.size() == 1;
+#endif
+  // TODO(kbr/zmo): on Windows, at least, it's now possible to have a
+  // system with both low-power and high-performance GPUs from AMD.
   const uint32_t kIntelID = 0x8086;
   bool saw_intel_gpu = false;
   bool saw_non_intel_gpu = false;

content/browser/gpu/gpu_internals_ui.cc

@@ -730,7 +730,7 @@ void GpuMessageHandler::OnGpuInfoUpdate() {
                                          *(gpu_info_val.get()));
 }
 
-void GpuMessageHandler::OnGpuSwitched(gl::GpuPreference active_gpu_heuristic_) {
+void GpuMessageHandler::OnGpuSwitched(gl::GpuPreference active_gpu_heuristic) {
   // Currently, about:gpu page does not update GPU info after the GPU switch.
   // If there is something to be updated, the code should be added here.
 }

third_party/blink/renderer/platform/graphics/gpu/drawing_buffer.cc

@@ -64,7 +64,6 @@
 #include "third_party/skia/include/core/SkSurface.h"
 #include "third_party/skia/include/gpu/GrContext.h"
 #include "third_party/skia/include/gpu/gl/GrGLTypes.h"
-#include "ui/gl/gpu_preference.h"
 #include "v8/include/v8.h"
 
 namespace blink {

third_party/blink/renderer/platform/graphics/gpu/drawing_buffer.h

@@ -611,7 +611,7 @@ class PLATFORM_EXPORT DrawingBuffer : public cc::TextureLayerClient,
 
   bool opengl_flip_y_extension_;
 
-  gl::GpuPreference initial_gpu_;
+  const gl::GpuPreference initial_gpu_;
   gl::GpuPreference current_active_gpu_;
 
   DISALLOW_COPY_AND_ASSIGN(DrawingBuffer);