Add GetStubStats and related functions in GpuMemoryManager.

content/common/gpu/gpu_memory_manager.h

Index: content/common/gpu/gpu_memory_manager.h
diff --git a/content/common/gpu/gpu_memory_manager.h b/content/common/gpu/gpu_memory_manager.h
index ecab989d857a02effd9b60836fc4ac2c296484e0..8e12e17c31b9748380982f6baf26e25f212328f0 100644
--- a/content/common/gpu/gpu_memory_manager.h
+++ b/content/common/gpu/gpu_memory_manager.h
@@ -8,11 +8,13 @@
 #if defined(ENABLE_GPU)
 
 #include <vector>
+#include <map>
 
 #include "base/basictypes.h"
 #include "base/cancelable_callback.h"
 #include "base/memory/weak_ptr.h"
 #include "content/common/content_export.h"
+#include "content/common/gpu/gpu_memory_allocation.h"
 
 class GpuCommandBufferStubBase;
 
@@ -46,6 +48,14 @@ class CONTENT_EXPORT GpuMemoryManager :
 #endif
   };
 
+  // StubMemoryStat is used to store memory-allocation-related information about
+  // a GpuCommandBufferStubBase for some time point.
+  struct StubMemoryStat {
+    bool visible;
+    GpuMemoryAllocationRequest requested_allocation;
+    GpuMemoryAllocation allocation;
+  };
+
   GpuMemoryManager(GpuMemoryManagerClient* client,
                    size_t max_surfaces_with_frontbuffer_soft_limit);
   ~GpuMemoryManager();
@@ -57,6 +67,26 @@ class CONTENT_EXPORT GpuMemoryManager :
   // queued delayed manage.
   void ScheduleManage(bool immediate);
 
+  // Returns StubMemoryStat's for each GpuCommandBufferStubBase, which were
+  // assigned during the most recent call to Manage().
+  // Useful for tracking the memory-allocation-related presumed state of the
+  // system, as seen by GpuMemoryManager.
+  std::map<GpuCommandBufferStubBase*, StubMemoryStat>

[piman, 2012/07/18 19:59:58]

I suggest returning const std::map<...>& to avoid copying this big data
structure.
Also, I suggest creating a typedef std::map<GpuCommandBufferStubBase*,
StubMemoryStat> StubMemoryStatMap.
Finally, you may be better served by a hash_map than a std::map, since you don't
care about the order of keys - it's cheaper in both memory and perf - ammortized
O(1) instead of O(log n).

+      GetStubStatsForLastManage() const {
+    return stub_memory_stats_;
+  }
+
+  // Tries to estimate the total available gpu memory for use by
+  // GpuMemoryManager.  Ideally should consider other system applications and
+  // other internal but non GpuMemoryManager managed sources, etc.
+  size_t GetAvailableGpuMemory() const;
+
+  // GetPeakAssignedAllocationSum() will return the historical max value for the
+  // sum of all assigned client allocations (ie, peak system memory allocation).
+  size_t GetPeakAssignedAllocationSum() const {

[piman, 2012/07/18 19:59:58]

nit: usually for trivial inline functions that just return a field, we name them
after the field itself. In this case, peak_assigned_allocation_sum().

+    return peak_assigned_allocation_sum_;
+  }
+
  private:
   friend class GpuMemoryManagerTest;
   void Manage();
@@ -74,6 +104,9 @@ class CONTENT_EXPORT GpuMemoryManager :
 
   size_t max_surfaces_with_frontbuffer_soft_limit_;
 
+  std::map<GpuCommandBufferStubBase*, StubMemoryStat> stub_memory_stats_;
+  size_t peak_assigned_allocation_sum_;
+
   DISALLOW_COPY_AND_ASSIGN(GpuMemoryManager);
 };