[cc] Use base::TimeTicks in RenderStats

cc/tile_manager.cc

Index: cc/tile_manager.cc
diff --git a/cc/tile_manager.cc b/cc/tile_manager.cc
index e7583bd20e40e03b4d551c3c98b004249d304ed5..4540b95577ba3e892dbf42bf220e263a0a59aa1b 100644
--- a/cc/tile_manager.cc
+++ b/cc/tile_manager.cc
@@ -255,8 +255,8 @@ void TileManager::GetRenderingStats(RenderingStats* stats) {
   stats->totalDeferredImageCacheHitCount =
       rendering_stats_.totalDeferredImageCacheHitCount;
   stats->totalImageGatheringCount = rendering_stats_.totalImageGatheringCount;
-  stats->totalImageGatheringTimeInSeconds =
-      rendering_stats_.totalImageGatheringTimeInSeconds;
+  stats->totalImageGatheringTime =
+      rendering_stats_.totalImageGatheringTime;
 }
 
 void TileManager::GetMemoryStats(
@@ -381,8 +381,8 @@ void TileManager::GatherPixelRefsForTile(Tile* tile) {
     const_cast<PicturePileImpl *>(tile->picture_pile())->GatherPixelRefs(
         tile->content_rect_, managed_state.pending_pixel_refs);
     rendering_stats_.totalImageGatheringCount++;
-    rendering_stats_.totalImageGatheringTimeInSeconds +=
-        (base::TimeTicks::Now() - gather_begin_time).InSecondsF();
+    rendering_stats_.totalImageGatheringTime +=
+        base::TimeTicks::Now() - gather_begin_time;
     managed_state.need_to_gather_pixel_refs = false;
   }
 }