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

Source/WebKit/chromium/src/WebViewImpl.cpp

Index: Source/WebKit/chromium/src/WebViewImpl.cpp
diff --git a/Source/WebKit/chromium/src/WebViewImpl.cpp b/Source/WebKit/chromium/src/WebViewImpl.cpp
index 73aaf97d0864969a9a4c5ef4abe069e83211c8b6..921eac1b880c1082e37e1f73b585d6d39beeea3b 100644
--- a/Source/WebKit/chromium/src/WebViewImpl.cpp
+++ b/Source/WebKit/chromium/src/WebViewImpl.cpp
@@ -2999,16 +2999,10 @@ void WebViewImpl::setPageScaleFactorLimits(float minPageScale, float maxPageScal
     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)
@@ -3663,24 +3657,22 @@ void WebViewImpl::layoutUpdated(WebFrameImpl* webframe)
         }
     }
 
-    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();