Remove DisplayCount from GpuDataManagerImpl.

content/browser/gpu/gpu_data_manager_impl_private.cc

Index: content/browser/gpu/gpu_data_manager_impl_private.cc
diff --git a/content/browser/gpu/gpu_data_manager_impl_private.cc b/content/browser/gpu/gpu_data_manager_impl_private.cc
index 0f5c572dc9b2dce5202adc405a88901239f50306..6e256d6e59fd5fce7064bec091f0329903645053 100644
--- a/content/browser/gpu/gpu_data_manager_impl_private.cc
+++ b/content/browser/gpu/gpu_data_manager_impl_private.cc
@@ -39,9 +39,6 @@
 #include "ui/gl/gl_switches.h"
 #include "ui/gl/gpu_switching_manager.h"
 
-#if defined(OS_MACOSX)
-#include <ApplicationServices/ApplicationServices.h>
-#endif  // OS_MACOSX
 #if defined(OS_WIN)
 #include "base/win/windows_version.h"
 #endif  // OS_WIN
@@ -214,40 +211,6 @@ std::string IntSetToString(const std::set<int>& list) {
   return rt;
 }
 
-#if defined(OS_MACOSX)
-void DisplayReconfigCallback(CGDirectDisplayID display,
-                             CGDisplayChangeSummaryFlags flags,
-                             void* gpu_data_manager) {
-  if (flags == kCGDisplayBeginConfigurationFlag)
-    return; // This call contains no information about the display change
-
-  GpuDataManagerImpl* manager =
-      reinterpret_cast<GpuDataManagerImpl*>(gpu_data_manager);
-  DCHECK(manager);
-
-  // Display change.
-  bool display_changed = false;
-  uint32_t displayCount;
-  CGGetActiveDisplayList(0, NULL, &displayCount);
-  if (displayCount != manager->GetDisplayCount()) {
-    manager->SetDisplayCount(displayCount);
-    display_changed = true;
-  }
-
-  // Gpu change.
-  bool gpu_changed = false;
-  if (flags & kCGDisplayAddFlag) {
-    uint32_t vendor_id, device_id;
-    if (gpu::CollectGpuID(&vendor_id, &device_id) == gpu::kCollectInfoSuccess) {
-      gpu_changed = manager->UpdateActiveGpu(vendor_id, device_id);
-    }
-  }
-
-  if (display_changed || gpu_changed)
-    manager->HandleGpuSwitch();

[danakj, 2016/04/05 00:51:57]

Uhh, maybe this is still needed.. oops.

[danakj, 2016/04/05 00:57:52]

HandleGpuSwitch() calls GpuSwitchingManager::NotifyGpuSwitched() and sends
GpuMsg_GpuSwitched to the GPU process.

NotifyGpuSwitched() was used to update WebPreferences in the browser process.

But other observers are:
- GpuMessageHandler::OnGpuSwitched() which calls
GpuDataManagerImpl::RequestCompleteGpuInfoIfNeeded();

uhh.. well that one is a complete circle, we were coming from the
GpuDataManagerImpl already.

I'm not actually seeing any overrides of OnGpuSwitched in the gpu process. Maybe
on other OSes that codesearch doesn't index.

[danakj, 2016/04/05 01:00:15]

Ok ya on MacOSX there are some more..

- ImageTransportSurfaceOverlayMac::OnGpuSwitched() which creates a new context.

- IOSurfaceContext::OnGpuSwitched() which poisons itself and its share group.

-}
-#endif  // OS_MACOSX
-
 // Block all domains' use of 3D APIs for this many milliseconds if
 // approaching a threshold where system stability might be compromised.
 const int64_t kBlockAllDomainsMs = 10000;
@@ -304,14 +267,6 @@ size_t GpuDataManagerImplPrivate::GetBlacklistedFeatureCount() const {
   return blacklisted_features_.size();
 }
 
-void GpuDataManagerImplPrivate::SetDisplayCount(unsigned int display_count) {
-  display_count_ = display_count;
-}
-
-unsigned int GpuDataManagerImplPrivate::GetDisplayCount() const {
-  return display_count_;
-}
-
 gpu::GPUInfo GpuDataManagerImplPrivate::GetGPUInfo() const {
   return gpu_info_;
 }
@@ -1000,7 +955,6 @@ GpuDataManagerImplPrivate::GpuDataManagerImplPrivate(GpuDataManagerImpl* owner)
       window_count_(0),
       domain_blocking_enabled_(true),
       owner_(owner),
-      display_count_(0),
       gpu_process_accessible_(true),
       is_initialized_(false),
       finalized_(false) {
@@ -1013,11 +967,6 @@ GpuDataManagerImplPrivate::GpuDataManagerImplPrivate(GpuDataManagerImpl* owner)
   if (command_line->HasSwitch(switches::kDisableGpu))
     DisableHardwareAcceleration();
 
-#if defined(OS_MACOSX)
-  CGGetActiveDisplayList (0, NULL, &display_count_);
-  CGDisplayRegisterReconfigurationCallback(DisplayReconfigCallback, owner_);
-#endif  // OS_MACOSX
-
   // For testing only.
   if (command_line->HasSwitch(switches::kDisableDomainBlockingFor3DAPIs)) {
     domain_blocking_enabled_ = false;
@@ -1025,9 +974,6 @@ GpuDataManagerImplPrivate::GpuDataManagerImplPrivate(GpuDataManagerImpl* owner)
 }
 
 GpuDataManagerImplPrivate::~GpuDataManagerImplPrivate() {
-#if defined(OS_MACOSX)
-  CGDisplayRemoveReconfigurationCallback(DisplayReconfigCallback, owner_);
-#endif
 }
 
 void GpuDataManagerImplPrivate::InitializeImpl(