Don't spam the GPU process with memory usage stats

cc/layer_tree_host_impl.cc

Index: cc/layer_tree_host_impl.cc
diff --git a/cc/layer_tree_host_impl.cc b/cc/layer_tree_host_impl.cc
index d9a2a08c3c267f6992a82613839b8c2e06ac9a87..3df81c250e986d9256e68da20460daa481e34361 100644
--- a/cc/layer_tree_host_impl.cc
+++ b/cc/layer_tree_host_impl.cc
@@ -33,6 +33,7 @@
 #include "cc/software_renderer.h"
 #include "cc/solid_color_draw_quad.h"
 #include "cc/texture_uploader.h"
+#include "cc/util.h"
 #include "ui/gfx/size_conversions.h"
 #include "ui/gfx/vector2d_conversions.h"
 
@@ -223,6 +224,9 @@ LayerTreeHostImpl::LayerTreeHostImpl(const LayerTreeSettings& settings, LayerTre
     , m_numMainThreadScrolls(0)
     , m_cumulativeNumLayersDrawn(0)
     , m_cumulativeNumMissingTiles(0)
+    , m_lastSentMemoryVisibleBytes(0)
+    , m_lastSentMemoryVisibleAndNearbyBytes(0)
+    , m_lastSentMemoryUseBytes(0)
 {
     DCHECK(m_proxy->isImplThread());
     didVisibilityChange(this, m_visible);
@@ -1584,6 +1588,34 @@ void LayerTreeHostImpl::renderingStats(RenderingStats* stats) const
         m_tileManager->renderingStats(stats);
 }
 
+void LayerTreeHostImpl::sendManagedMemoryStats(
+    size_t memoryVisibleBytes,
+    size_t memoryVisibleAndNearbyBytes,
+    size_t memoryUseBytes)
+{
+    if (!renderer())
+      return;
+
+    // Round the numbers being sent up to the next 8MB, to throttle the rate
+    // at which we spam the GPU process.
+    static const size_t roundingStep = 8 * 1024 * 1024;
+    memoryVisibleBytes = RoundUp(memoryVisibleBytes, roundingStep);
+    memoryVisibleAndNearbyBytes = RoundUp(memoryVisibleAndNearbyBytes, roundingStep);
+    memoryUseBytes = RoundUp(memoryUseBytes, roundingStep);
+    if (m_lastSentMemoryVisibleBytes == memoryVisibleBytes &&
+        m_lastSentMemoryVisibleAndNearbyBytes == memoryVisibleAndNearbyBytes &&
+        m_lastSentMemoryUseBytes == memoryUseBytes) {
+        return;
+    }
+    m_lastSentMemoryVisibleBytes = memoryVisibleBytes;
+    m_lastSentMemoryVisibleAndNearbyBytes = memoryVisibleAndNearbyBytes;
+    m_lastSentMemoryUseBytes = memoryUseBytes;
+
+    renderer()->sendManagedMemoryStats(m_lastSentMemoryVisibleBytes,
+                                       m_lastSentMemoryVisibleAndNearbyBytes,
+                                       m_lastSentMemoryUseBytes);
+}
+
 void LayerTreeHostImpl::animateScrollbars(base::TimeTicks time)
 {
     animateScrollbarsRecursive(rootLayer(), time);