Mark layers that can use LCD text based on layer transform and opacity.

cc/layer_tree_host.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layer_tree_host.h"
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/message_loop.h"
 #include "base/string_number_conversions.h"
@@ skipping 85 matching lines @@
 LayerTreeSettings::LayerTreeSettings()
     : acceleratePainting(false)
     , implSidePainting(false)
     , renderVSyncEnabled(true)
     , perTilePaintingEnabled(false)
     , partialSwapEnabled(false)
     , acceleratedAnimationEnabled(true)
     , pageScalePinchZoomEnabled(false)
     , backgroundColorInsteadOfCheckerboard(false)
     , showOverdrawInTracing(false)
+    , canUseLCDText(true)
     , refreshRate(0)
     , maxPartialTextureUpdates(std::numeric_limits<size_t>::max())
     , numRasterThreads(1)
     , defaultTileSize(gfx::Size(256, 256))
     , maxUntiledLayerSize(gfx::Size(512, 512))
     , minimumOcclusionTrackingSize(gfx::Size(160, 160))
 {
     // TODO(danakj): Move this to chromium when we don't go through the WebKit API anymore.
     implSidePainting = CommandLine::ForCurrentProcess()->HasSwitch(cc::switches::kEnableImplSidePainting);
     partialSwapEnabled = CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnablePartialSwap);
     backgroundColorInsteadOfCheckerboard = CommandLine::ForCurrentProcess()->HasSwitch(switches::kBackgroundColorInsteadOfCheckerboard);
     showOverdrawInTracing = CommandLine::ForCurrentProcess()->HasSwitch(switches::kTraceOverdraw);
 
+// TODO(alokp): Remove this hard-coded setting.
+// Platforms that need to disable LCD text must explicitly set this value.
+#if defined(OS_ANDROID)
+    canUseLCDText = false;
+#endif
+
     initialDebugState.showPropertyChangedRects = CommandLine::ForCurrentProcess()->HasSwitch(cc::switches::kShowPropertyChangedRects);
     initialDebugState.showSurfaceDamageRects = CommandLine::ForCurrentProcess()->HasSwitch(cc::switches::kShowSurfaceDamageRects);
     initialDebugState.showScreenSpaceRects = CommandLine::ForCurrentProcess()->HasSwitch(cc::switches::kShowScreenSpaceRects);
     initialDebugState.showReplicaScreenSpaceRects = CommandLine::ForCurrentProcess()->HasSwitch(cc::switches::kShowReplicaScreenSpaceRects);
     initialDebugState.showOccludingRects = CommandLine::ForCurrentProcess()->HasSwitch(cc::switches::kShowOccludingRects);
     initialDebugState.showNonOccludingRects = CommandLine::ForCurrentProcess()->HasSwitch(cc::switches::kShowNonOccludingRects);
 
     if (CommandLine::ForCurrentProcess()->HasSwitch(
             switches::kNumRasterThreads)) {
         const size_t kMaxRasterThreads = 64;
@@ skipping 545 matching lines @@
     LayerList updateList;
 
     {
         if (m_settings.pageScalePinchZoomEnabled) {
             Layer* rootScroll = findFirstScrollableLayer(rootLayer);
             if (rootScroll)
                 rootScroll->setImplTransform(m_implTransform);
         }
 
         TRACE_EVENT0("cc", "LayerTreeHost::updateLayers::calcDrawEtc");
-        LayerTreeHostCommon::calculateDrawProperties(rootLayer, deviceViewportSize(), m_deviceScaleFactor, m_pageScaleFactor, rendererCapabilities().maxTextureSize, updateList);
+        LayerTreeHostCommon::calculateDrawProperties(rootLayer, deviceViewportSize(), m_deviceScaleFactor, m_pageScaleFactor, rendererCapabilities().maxTextureSize, m_settings.canUseLCDText, updateList);
     }
 
     // Reset partial texture update requests.
     m_partialTextureUpdateRequests = 0;
 
     bool needMoreUpdates = paintLayerContents(updateList, queue);
     if (m_triggerIdleUpdates && needMoreUpdates) {
         TRACE_EVENT0("cc", "LayerTreeHost::updateLayers::posting prepaint task");
         m_prepaintCallback.Reset(base::Bind(&LayerTreeHost::triggerPrepaint, base::Unretained(this)));
         static base::TimeDelta prepaintDelay = base::TimeDelta::FromMilliseconds(100);
@@ skipping 279 matching lines @@
             else
                 layer->notifyAnimationFinished(wallClockTime.ToDoubleT());
         }
     }
 
     for (size_t childIndex = 0; childIndex < layer->children().size(); ++childIndex)
         setAnimationEventsRecursive(events, layer->children()[childIndex].get(), wallClockTime);
 }
 
 }  // namespace cc