Change GpuDataManager to use Observer notifications rather than callbacks

content/browser/gpu/gpu_data_manager.cc

Index: content/browser/gpu/gpu_data_manager.cc
===================================================================
--- content/browser/gpu/gpu_data_manager.cc	(revision 107010)
+++ content/browser/gpu/gpu_data_manager.cc	(working copy)
@@ -8,6 +8,8 @@
 #include <CoreGraphics/CGDisplayConfiguration.h>
 #endif
 
+#include "base/bind.h"
+#include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
 #include "base/stringprintf.h"
@@ -187,7 +189,8 @@
 }
 
 GpuDataManager::GpuDataManager()
-    : complete_gpu_info_already_requested_(false) {
+    : complete_gpu_info_already_requested_(false),
+      observer_list_(new GpuDataManagerObserverList) {
   Initialize();
 }
 
@@ -239,7 +242,7 @@
       return;
   }
 
-  RunGpuInfoUpdateCallbacks();
+  NotifyGpuInfoUpdate();
 
   {
     base::AutoLock auto_lock(gpu_info_lock_);
@@ -410,20 +413,12 @@
   return (gpu_feature_flags_.flags() & mask) == 0;
 }
 
-void GpuDataManager::AddGpuInfoUpdateCallback(Callback0::Type* callback) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  gpu_info_update_callbacks_.insert(callback);
+void GpuDataManager::AddObserver(Observer* observer) {
+  observer_list_->AddObserver(observer);
 }
 
-bool GpuDataManager::RemoveGpuInfoUpdateCallback(Callback0::Type* callback) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  std::set<Callback0::Type*>::iterator i =
-      gpu_info_update_callbacks_.find(callback);
-  if (i != gpu_info_update_callbacks_.end()) {
-    gpu_info_update_callbacks_.erase(i);
-    return true;
-  }
-  return false;
+void GpuDataManager::RemoveObserver(Observer* observer) {
+  observer_list_->RemoveObserver(observer);
 }
 
 void GpuDataManager::AppendRendererCommandLine(
@@ -570,23 +565,16 @@
   return info;
 }
 
-void GpuDataManager::RunGpuInfoUpdateCallbacks() {
-  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-        NewRunnableMethod(this, &GpuDataManager::RunGpuInfoUpdateCallbacks));
-    return;
-  }
-
-  std::set<Callback0::Type*>::iterator i = gpu_info_update_callbacks_.begin();
-  for (; i != gpu_info_update_callbacks_.end(); ++i) {
-    (*i)->Run();
-  }
+void GpuDataManager::NotifyGpuInfoUpdate() {
+  observer_list_->Notify(&GpuDataManager::Observer::OnGpuInfoUpdate);
 }
 
 void GpuDataManager::UpdateGpuFeatureFlags() {
   if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-        NewRunnableMethod(this, &GpuDataManager::UpdateGpuFeatureFlags));
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE,
+        base::Bind(&GpuDataManager::UpdateGpuFeatureFlags,
+                   base::Unretained(this)));

[James Hawkins, 2011/10/25 23:36:52]

Is base::Unretained() really needed here?  The conversion is from
NewRunnableMethod, which implies the ref-counting is desired.

[csilv, 2011/10/26 00:02:47]

So, in the original implementation NewRunnableMethod is not ref counting due to
use of:

  DISABLE_RUNNABLE_METHOD_REFCOUNT(GpuDataManager);

So that line needs to be deleted and thus the above represents a correct
migration.  GpuDataManger is a singleton so stays around until app exit.  The
alternative would be to make GpuDataManger a ref-counted object and then get rid
of the Unretained usage.

[James Hawkins, 2011/10/26 00:21:29]

Gotcha.

     return;
   }
 
@@ -605,7 +593,7 @@
   }
 
   // Notify clients that GpuInfo state has changed
-  RunGpuInfoUpdateCallbacks();
+  NotifyGpuInfoUpdate();
 
   uint32 flags = gpu_feature_flags_.flags();
   uint32 max_entry_id = gpu_blacklist->max_entry_id();