Widen GPU trigger condition

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index d545e9f50f213cd7e0a3be3d5786e3d189963ab1..378674b1496e76bc703a39aa23a3d78bc4ac2d6f 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -3251,12 +3251,6 @@ void WebViewImpl::updatePageDefinedViewportConstraints(const ViewportDescription
 
     Document* document = page()->deprecatedLocalMainFrame()->document();
 
-    m_matchesHeuristicsForGpuRasterization = description.maxWidth == Length(DeviceWidth)
-        && description.minZoom == 1.0
-        && description.minZoomIsExplicit;
-    if (m_layerTreeView)
-        m_layerTreeView->heuristicsForGpuRasterizationUpdated(m_matchesHeuristicsForGpuRasterization);
-
     Length defaultMinWidth = document->viewportDefaultMinWidth();
     if (defaultMinWidth.isAuto())
         defaultMinWidth = Length(ExtendToZoom);
@@ -3283,6 +3277,12 @@ void WebViewImpl::updatePageDefinedViewportConstraints(const ViewportDescription
             setInitialPageScaleOverride(-1);
     }
 
+    m_matchesHeuristicsForGpuRasterization = description.maxWidth == Length(DeviceWidth)
+        && (m_pageScaleConstraintsSet.pageDefinedConstraints().minimumScale >= 1.0
+            || (!description.userZoom && m_pageScaleConstraintsSet.pageDefinedConstraints().initialScale >= 1.0));
+    if (m_layerTreeView)
+        m_layerTreeView->heuristicsForGpuRasterizationUpdated(m_matchesHeuristicsForGpuRasterization);
+

[ajuma, 2014/10/21 17:40:03]

I understand the motivation of using the resolved values, but I think it makes
things harder to explain to web developers. I'd prefer to do something similar
using |description| directly (as before). For example, how about:
 m_matchesHeuristicsForGpuRasterization = description.maxWidth ==
Length(DeviceWidth)	
         && ((description.minZoom >= 1.0 && description.minZoomIsExplicit)
             || (description.userZoom == false && description.zoom >= 1.0 &&
description.zoomIsExplicit));

This allows viewports that meet either of the following conditions:
1) width=device-width, minimum-scale=X, where X >= 1.0
2) width=device-width, user-scalable=no, initial-scale=X, where X >= 1.0

     m_pageScaleConstraintsSet.adjustForAndroidWebViewQuirks(adjustedDescription, defaultMinWidth.intValue(), deviceScaleFactor(), settingsImpl()->supportDeprecatedTargetDensityDPI(), page()->settings().wideViewportQuirkEnabled(), page()->settings().useWideViewport(), page()->settings().loadWithOverviewMode(), settingsImpl()->viewportMetaNonUserScalableQuirk());
     float newInitialScale = m_pageScaleConstraintsSet.pageDefinedConstraints().initialScale;
     if (oldInitialScale != newInitialScale && newInitialScale != -1) {