Bug 934783 - Fix GPU memory reporter for win7 and reenable. r=njn

gfx/thebes/d3dkmtQueryStatistics.h

@@ -104,7 +104,15 @@ typedef struct _D3DKMTQS_PROCESS_INFO
 
 typedef struct _D3DKMTQS_PROCESS_SEGMENT_INFO
 {
-    ULONGLONG BytesCommitted;
+    union {
+        struct {
+            ULONGLONG BytesCommitted;
+        } Win8;
+        struct {
+            ULONG BytesCommitted;
+            ULONG UnknownRandomness;
+        } Win7;
+    };
 
     ULONGLONG Filler[2];
     ULONG Filler2;

gfx/thebes/gfxWindowsPlatform.cpp

@@ -239,14 +239,15 @@ public:
                         queryStatistics.hProcess = ProcessHandle;
                         queryStatistics.QueryProcessSegment.SegmentId = i;
                         if (NT_SUCCESS(queryD3DKMTStatistics(&queryStatistics))) {
-                            if (aperture)
-                                sharedBytesUsed += queryStatistics.QueryResult
-                                                                  .ProcessSegmentInfo
-                                                                  .BytesCommitted;
+                            ULONGLONG bytesCommitted;
+                            if (!IsWin8OrLater())
+                                bytesCommitted = queryStatistics.QueryResult.ProcessSegmentInfo.Win7.BytesCommitted;
                             else
-                                dedicatedBytesUsed += queryStatistics.QueryResult
-                                                                     .ProcessSegmentInfo
-                                                                     .BytesCommitted;
+                                bytesCommitted = queryStatistics.QueryResult.ProcessSegmentInfo.Win8.BytesCommitted;
+                            if (aperture)
+                                sharedBytesUsed += bytesCommitted;
+                            else
+                                dedicatedBytesUsed += bytesCommitted;
                         }
                     }
                 }
@@ -312,9 +313,7 @@ gfxWindowsPlatform::gfxWindowsPlatform()
 
     UpdateRenderMode();
 
-    // This reporter is disabled because it frequently gives bogus values.  See
-    // bug 917496.
-    //RegisterStrongMemoryReporter(new GPUAdapterReporter());
+    RegisterStrongMemoryReporter(new GPUAdapterReporter());
 }
 
 gfxWindowsPlatform::~gfxWindowsPlatform()