Reset page scale factor to 1.0 on navigation to a new page.

Source/WebKit/chromium/src/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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 2981 matching lines @@
 }
 
 void WebViewImpl::setPageScaleFactorLimits(float minPageScale, float maxPageScale)
 {
     if (minPageScale == m_pageDefinedMinimumPageScaleFactor && maxPageScale == m_pageDefinedMaximumPageScaleFactor)
         return;
 
     m_pageDefinedMinimumPageScaleFactor = minPageScale;
     m_pageDefinedMaximumPageScaleFactor = maxPageScale;
 
-    if (settings()->viewportEnabled()) {
-        // If we're in viewport tag mode, we need to layout to obtain the latest
-        // contents size and compute the final limits.
-        FrameView* view = mainFrameImpl()->frameView();
-        if (view)
-            view->setNeedsLayout();
-    } else {
-        // Otherwise just compute the limits immediately.
-        computePageScaleFactorLimits();
-    }
+    // Obtain the latest contents size and compute the final limits.
+    FrameView* view = mainFrameImpl()->frameView();
+    if (view)
+        view->setNeedsLayout();
 }
 
 void WebViewImpl::setIgnoreViewportTagMaximumScale(bool flag)
 {
     m_ignoreViewportTagMaximumScale = flag;
 
     if (!page() || !page()->mainFrame())
         return;
 
     m_page->chrome()->client()->dispatchViewportPropertiesDidChange(page()->mainFrame()->document()->viewportArguments());
@@ skipping 634 matching lines @@
 
     if (m_shouldAutoResize && mainFrameImpl()->frame() && mainFrameImpl()->frame()->view()) {
         WebSize frameSize = mainFrameImpl()->frame()->view()->frameRect().size();
         if (frameSize != m_size) {
             m_size = frameSize;
             m_client->didAutoResize(m_size);
             sendResizeEventAndRepaint();
         }
     }
 
-    if (settings()->viewportEnabled()) {
-        if (!isPageScaleFactorSet()) {
-            // If the viewport tag failed to be processed earlier, we need
-            // to recompute it now.
-            ViewportArguments viewportArguments = mainFrameImpl()->frame()->document()->viewportArguments();
-            m_page->chrome()->client()->dispatchViewportPropertiesDidChange(viewportArguments);
-        }
+    if (settings()->viewportEnabled() && !isPageScaleFactorSet()) {
+        // If the viewport tag failed to be processed earlier, we need
+        // to recompute it now.
+        ViewportArguments viewportArguments = mainFrameImpl()->frame()->document()->viewportArguments();
+        m_page->chrome()->client()->dispatchViewportPropertiesDidChange(viewportArguments);
+    }
 
-        // Contents size is an input to the page scale limits, so a good time to
-        // recalculate is after layout has occurred.
-        computePageScaleFactorLimits();
+    // Contents size is an input to the page scale limits, so a good time to

[jamesr, 2013/05/03 17:55:58]

do you really need to do all this work on every layoutUpdated()? can you skip it
when the page scale factor limits are 1.0/1.0?

[wjmaclean, 2013/05/03 18:26:17]

I think so ... will upload new patch shortly.

[aelias_OOO_until_Jul13, 2013/05/03 21:00:50]

We shouldn't avoid calling this based on pageScaleFactorLimits being 1.0/1.0,
that is circular.  If we really wanted to avoid calling this we should have a
new setting along the lines of "pageScaleFactorLockedTo1".

But I don't understand your concern about "all this work".  It's some O(1)
arithmetic, it doesn't walk any data structures.  If nothing changes, it won't
relayout either.  I think we should just always call it.

+    // recalculate is after layout has occurred.
+    computePageScaleFactorLimits();
 
-        // Relayout immediately to avoid violating the rule that needsLayout()
-        // isn't set at the end of a layout.
-        FrameView* view = mainFrameImpl()->frameView();
-        if (view && view->needsLayout())
-            view->layout();
-    }
+    // Relayout immediately to avoid violating the rule that needsLayout()
+    // isn't set at the end of a layout.
+    FrameView* view = mainFrameImpl()->frameView();
+    if (view && view->needsLayout())
+        view->layout();
 
     m_client->didUpdateLayout();
 
 }
 
 void WebViewImpl::didChangeContentsSize()
 {
 }
 
 void WebViewImpl::deviceOrPageScaleFactorChanged()
@@ skipping 516 matching lines @@
 }
 
 bool WebViewImpl::shouldDisableDesktopWorkarounds()
 {
     ViewportArguments arguments = mainFrameImpl()->frame()->document()->viewportArguments();
     return arguments.width == ViewportArguments::ValueDeviceWidth || !arguments.userZoom
         || (arguments.minZoom == arguments.maxZoom && arguments.minZoom != ViewportArguments::ValueAuto);
 }
 
 } // namespace WebKit