Add calls to inform gpu of browser window count

chrome/browser/chrome_gpu_util.cc

Index: chrome/browser/chrome_gpu_util.cc
diff --git a/chrome/browser/chrome_gpu_util.cc b/chrome/browser/chrome_gpu_util.cc
index b4221eca6e88addc629eef7120cd5ce02686f87c..af2c57e4d1270b504b4f429cf03856728bcd6f4b 100644
--- a/chrome/browser/chrome_gpu_util.cc
+++ b/chrome/browser/chrome_gpu_util.cc
@@ -11,6 +11,9 @@
 #if defined(OS_WIN)
 #include "base/win/windows_version.h"
 #endif
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_list.h"
+#include "chrome/browser/ui/browser_list_observer.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/chrome_version_info.h"
 #include "content/public/browser/gpu_data_manager.h"
@@ -21,6 +24,34 @@ using content::GpuDataManager;
 
 namespace gpu_util {
 
+// The BrowserMonitor class is used to track the number of currently open
+// browser windows, so that the gpu can be notified when they are created or
+// destroyed. We only count tabbed windows for this purpose.
+class BrowserMonitor : public chrome::BrowserListObserver {
+ public:
+  BrowserMonitor() : num_browsers_(0) {
+    BrowserList::AddObserver(this);
+  }
+
+  ~BrowserMonitor() {
+    BrowserList::RemoveObserver(this);
+  }
+
+ private:
+  // BrowserListObserver implementation.
+  virtual void OnBrowserAdded(Browser* browser) OVERRIDE {
+    if (browser->type() == Browser::TYPE_TABBED)
+      content::GpuDataManager::GetInstance()->SetWindowCount(++num_browsers_);
+  }
+
+  virtual void OnBrowserRemoved(Browser* browser) OVERRIDE {
+    if (browser->type() == Browser::TYPE_TABBED)
+      content::GpuDataManager::GetInstance()->SetWindowCount(--num_browsers_);
+  }
+
+  uint32 num_browsers_;
+};
+
 bool ShouldRunStage3DFieldTrial() {
 #if !defined(OS_WIN)
   return false;
@@ -157,5 +188,9 @@ void InitializeCompositingFieldTrial() {
   UMA_HISTOGRAM_BOOLEAN("GPU.InCompositorThreadFieldTrial", thread);
 }
 
+void InitializeBrowserMonitor() {

[ccameron, 2012/10/02 02:06:43]

Will leak detection complain about this?  If there a way we should scope this or
track it to make sure that we don't create multiple instances?

[DaveMoore, 2012/10/03 20:06:55]

Changed it to a singleton that won't trigger leak detection.

On 2012/10/02 02:06:43, ccameron1 wrote:

+  BrowserList::AddObserver(new BrowserMonitor);
+}
+
 }  // namespace gpu_util;