Add Settings::deviceScaleAdjustment.

Source/core/rendering/TextAutosizer.cpp

Index: Source/core/rendering/TextAutosizer.cpp
diff --git a/Source/core/rendering/TextAutosizer.cpp b/Source/core/rendering/TextAutosizer.cpp
index 0424b5a6e365d27923be17813dc1644291d63025..044d80e93749abd26dc2b782ab85757f4b2ac61d 100644
--- a/Source/core/rendering/TextAutosizer.cpp
+++ b/Source/core/rendering/TextAutosizer.cpp
@@ -208,6 +208,12 @@ float TextAutosizer::clusterMultiplier(WritingMode writingMode, const TextAutosi
 
     float multiplier = logicalClusterWidth / logicalWindowWidth;
     multiplier *= m_document->settings()->textAutosizingFontScaleFactor();
+
+    // If the page has a meta viewport or @viewport, don't apply the device scale adjustment.
+    const ViewportDescription& viewportDescription = m_document->page()->mainFrame()->document()->viewportDescription();
+    if (!viewportDescription.isSpecifiedByAuthor()) {

[johnme, 2013/11/05 18:56:40]

Didn't we say we'd disable the fontScaleFactor if you have a <= device-width
viewport, or an unscalable viewport? But I didn't think we wanted to disable it
for e.g. a width=1000 viewport.

IIRC the check you want here is the same as I added in
https://codereview.chromium.org/18850005/diff/446001/content/public/android/j...
for disabling double tap zoom, though you'd need to get the values from Blink
not Java :)

[skobes, 2013/11/05 19:02:46]

Actually what we are doing is disabling the 1.05-1.3x multiplier on the font
scale factor for sites with a meta viewport (I believe this is the proposal we
agreed on in our last meeting).  We will still autosize when layout width >
device width.

+        multiplier *= m_document->settings()->deviceScaleAdjustment();
+    }
     return std::max(1.0f, multiplier);
 }