cc: Add four new histograms for gpu image decode/upload usage tracking.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 8353983edbd91f47590efa597200b7f9ba0b5282..02f75c73e8a4c330325c8423c70a8cc3cbf7bbcc 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -44254,6 +44254,43 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Renderer4.GpuImageDecodeState" enum="GpuImageDecodeState">
+  <owner>vmpstr@chromium.org</owner>
+  <summary>
+    Gpu image decode usage statistics. Images are decoded and locked prior to
+    upload; this indicates how that decode is used during tile management.
+  </summary>
+</histogram>
+
+<histogram name="Renderer4.GpuImageDecodeState.FirstLockWasted"
+    enum="BooleanWasted">
+  <owner>vmpstr@chromium.org</owner>
+  <summary>
+    Indication whether the first lock of an image decode was wasted (image was
+    not used). Images are decoded and locked prior to raster; this indicates
+    whether the decode was used or not during the first lock.
+  </summary>
+</histogram>
+
+<histogram name="Renderer4.GpuImageUploadState.FirstRefWasted"
+    enum="BooleanWasted">
+  <owner>vmpstr@chromium.org</owner>
+  <summary>
+    Indication whether the first ref of a GPU image upload was wasted (not used
+    in raster). Images are uploaded prior to raster; this indicates whether the
+    upload was used during the first ref.
+  </summary>
+</histogram>
+
+<histogram name="Renderer4.GpuImageUploadState.Used" enum="BooleanUsage">
+  <owner>vmpstr@chromium.org</owner>
+  <summary>
+    Indication whether the GPU image upload was used in raster. Images are
+    uploaded prior to raster; this indicates whether the upload was used during
+    raster.
+  </summary>
+</histogram>
+
 <histogram name="Renderer4.GpuRasterizationEnabled" enum="BooleanEnabled">
   <owner>alokp@chromium.org</owner>
   <summary>
@@ -75987,6 +76024,13 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="5" label="UPGRADE_ERROR"/>
 </enum>
 
+<enum name="GpuImageDecodeState" type="int">
+  <int value="0" label="Wasted, once"/>
+  <int value="1" label="Used, once"/>
+  <int value="2" label="Wasted, relocked"/>
+  <int value="3" label="Used, relocked"/>
+</enum>
+
 <enum name="GPUProcessLaunchCauses" type="int">
   <summary>
     Causes for the GPU Process to be launched. From: