Add GPU memory tab to the task manager.

content/common/gpu/gpu_memory_manager.cc

Index: content/common/gpu/gpu_memory_manager.cc
diff --git a/content/common/gpu/gpu_memory_manager.cc b/content/common/gpu/gpu_memory_manager.cc
index 945894e0c43f366039f4f6fd049c8992b6e91953..73469abf097b4df4c4b4a02a4eb8fcc830eb913a 100644
--- a/content/common/gpu/gpu_memory_manager.cc
+++ b/content/common/gpu/gpu_memory_manager.cc
@@ -12,9 +12,11 @@
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/message_loop.h"
+#include "base/process_util.h"
 #include "base/string_number_conversions.h"
 #include "content/common/gpu/gpu_command_buffer_stub.h"
 #include "content/common/gpu/gpu_memory_allocation.h"
+#include "content/common/gpu/gpu_memory_tracking.h"
 #include "gpu/command_buffer/service/gpu_switches.h"
 
 namespace {
@@ -92,6 +94,7 @@ GpuMemoryManager::GpuMemoryManager(GpuMemoryManagerClient* client,
 }
 
 GpuMemoryManager::~GpuMemoryManager() {
+  DCHECK(tracking_groups_.empty());
 }
 
 bool GpuMemoryManager::StubWithSurfaceComparator::operator()(
@@ -129,8 +132,7 @@ void GpuMemoryManager::ScheduleManage(bool immediate) {
 }
 
 void GpuMemoryManager::TrackMemoryAllocatedChange(size_t old_size,
-                                                  size_t new_size)
-{
+                                                  size_t new_size) {
   if (new_size < old_size) {
     size_t delta = old_size - new_size;
     DCHECK(bytes_allocated_current_ >= delta);
@@ -150,6 +152,34 @@ void GpuMemoryManager::TrackMemoryAllocatedChange(size_t old_size,
   }
 }
 
+void GpuMemoryManager::AddTrackingGroup(
+    GpuMemoryTrackingGroup* tracking_group) {
+  tracking_groups_.insert(tracking_group);
+}
+
+void GpuMemoryManager::RemoveTrackingGroup(
+    GpuMemoryTrackingGroup* tracking_group) {
+  tracking_groups_.erase(tracking_group);
+}
+
+void GpuMemoryManager::GetVideoMemoryUsageStats(
+    content::GPUVideoMemoryUsageStats& video_memory_usage_stats) const {
+  // For each context group, assign its memory usage to its PID
+  video_memory_usage_stats.process_map.clear();
+  for (std::set<GpuMemoryTrackingGroup*>::const_iterator i =
+       tracking_groups_.begin(); i != tracking_groups_.end(); ++i) {
+    const GpuMemoryTrackingGroup* tracking_group = (*i);
+    video_memory_usage_stats.process_map[
+        tracking_group->GetPid()].video_memory += tracking_group->GetSize();
+  }
+
+  // Assign the total across all processes in the GPU process
+  video_memory_usage_stats.process_map[
+      base::GetCurrentProcId()].video_memory = bytes_allocated_current_;
+  video_memory_usage_stats.process_map[
+      base::GetCurrentProcId()].has_duplicates = true;
+}
+
 // The current Manage algorithm simply classifies contexts (stubs) into
 // "foreground", "background", or "hibernated" categories.
 // For each of these three categories, there are predefined memory allocation