Fix page zoom to be frame-centric for out-of-process frames.

third_party/WebKit/Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
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  *     * Redistributions in binary form must reproduce the above
@@ skipping 3046 matching lines @@
     // TODO(alexmos): Pass in proper with sourceCapabilities.
     page()->focusController().advanceFocusAcrossFrames(
         type, toWebRemoteFrameImpl(from)->frame(), toWebLocalFrameImpl(to)->frame());
 }
 
 double WebViewImpl::zoomLevel()
 {
     return m_zoomLevel;
 }
 
+void WebViewImpl::propagateZoomToLocalFrameRoots(Frame* frame)
+{
+    if (frame->isLocalRoot()) {
+        LocalFrame* localFrame = toLocalFrame(frame);
+
+        if (!WebLocalFrameImpl::pluginContainerFromFrame(localFrame)) {
+            float zoomFactor = m_zoomFactorOverride ? m_zoomFactorOverride : static_cast<float>(zoomLevelToZoomFactor(m_zoomLevel));
+            if (m_zoomFactorForDeviceScaleFactor) {
+                if (m_compositorDeviceScaleFactorOverride) {
+                    // Adjust the page's DSF so that DevicePixelRatio becomes m_zoomFactorForDeviceScaleFactor.
+                    page()->setDeviceScaleFactor(m_zoomFactorForDeviceScaleFactor / m_compositorDeviceScaleFactorOverride);

[dcheng, 2016/04/29 22:49:15]

Why do we call the Page methods for each invocation of
propagateZoomToLocalFrameRoots()? Shouldn't that be a one-time top-level
calculation? The only thing I would expect to be invoked here is
Frame::setPageZoomFactor.

In addition, does it make sense for zoom factor to be set on a per-frame basis
in Blink? Maybe it should be per Page, with a didChangeZoomFactor() call if some
state on LocalFrame needs to be updated?

+                    zoomFactor *= m_compositorDeviceScaleFactorOverride;
+                } else {
+                    page()->setDeviceScaleFactor(1.f);
+                    zoomFactor *= m_zoomFactorForDeviceScaleFactor;
+                }
+            }
+            localFrame->setPageZoomFactor(zoomFactor);
+        }
+    }
+
+    for (Frame* child = frame->tree().firstChild(); child; child = child->tree().nextSibling())
+        propagateZoomToLocalFrameRoots(child);
+}
+
 double WebViewImpl::setZoomLevel(double zoomLevel)
 {
     if (zoomLevel < m_minimumZoomLevel)
         m_zoomLevel = m_minimumZoomLevel;
     else if (zoomLevel > m_maximumZoomLevel)
         m_zoomLevel = m_maximumZoomLevel;
     else
         m_zoomLevel = zoomLevel;
 
-    // TODO(nasko): Setting zoom level needs to be refactored to support
-    // out-of-process iframes. See https://crbug.com/528407.
-    if (mainFrame()->isWebRemoteFrame())
-        return m_zoomLevel;
-
-    LocalFrame* frame = mainFrameImpl()->frame();
-    if (!WebLocalFrameImpl::pluginContainerFromFrame(frame)) {
-        float zoomFactor = m_zoomFactorOverride ? m_zoomFactorOverride : static_cast<float>(zoomLevelToZoomFactor(m_zoomLevel));
-        if (m_zoomFactorForDeviceScaleFactor) {
-            if (m_compositorDeviceScaleFactorOverride) {
-                // Adjust the page's DSF so that DevicePixelRatio becomes m_zoomFactorForDeviceScaleFactor.
-                page()->setDeviceScaleFactor(m_zoomFactorForDeviceScaleFactor / m_compositorDeviceScaleFactorOverride);
-                zoomFactor *= m_compositorDeviceScaleFactorOverride;
-            } else {
-                page()->setDeviceScaleFactor(1.f);
-                zoomFactor *= m_zoomFactorForDeviceScaleFactor;
-            }
-        }
-        frame->setPageZoomFactor(zoomFactor);
-    }
+    propagateZoomToLocalFrameRoots(m_page->mainFrame());
 
     return m_zoomLevel;
 }
 
 void WebViewImpl::zoomLimitsChanged(double minimumZoomLevel,
                                     double maximumZoomLevel)
 {
     m_minimumZoomLevel = minimumZoomLevel;
     m_maximumZoomLevel = maximumZoomLevel;
     m_client->zoomLimitsChanged(m_minimumZoomLevel, m_maximumZoomLevel);
@@ skipping 1412 matching lines @@
 {
     // TODO(oshima): Investigate if this should return the ScreenInfo's scale factor rather than
     // page's scale factor, which can be 1 in use-zoom-for-dsf mode.
     if (!page())
         return 1;
 
     return page()->deviceScaleFactor();
 }
 
 } // namespace blink