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

third_party/WebKit/Source/web/WebViewImpl.cpp

Index: third_party/WebKit/Source/web/WebViewImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebViewImpl.cpp b/third_party/WebKit/Source/web/WebViewImpl.cpp
index 107878abf2a9750ffbc8f1fbdcf4cac5e29e5b78..dbce5b06b65f7e4ff4ef9e4783670e765bcfada8 100644
--- a/third_party/WebKit/Source/web/WebViewImpl.cpp
+++ b/third_party/WebKit/Source/web/WebViewImpl.cpp
@@ -3064,6 +3064,31 @@ 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)
@@ -3073,26 +3098,7 @@ double WebViewImpl::setZoomLevel(double zoomLevel)
     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;
 }