[Android WebView] Add a legacy quirk for 'user-scalable=no' case

Source/web/WebSettingsImpl.h

Index: Source/web/WebSettingsImpl.h
diff --git a/Source/web/WebSettingsImpl.h b/Source/web/WebSettingsImpl.h
index 863f6c9ebc453f0266111fd4fe67eede685ee863..3e7906576a38ed393b29ab013653156d0063d596 100644
--- a/Source/web/WebSettingsImpl.h
+++ b/Source/web/WebSettingsImpl.h
@@ -173,6 +173,7 @@ public:
     virtual void setViewportEnabled(bool);
     virtual void setViewportMetaLayoutSizeQuirk(bool);
     virtual void setViewportMetaMergeContentQuirk(bool);
+    virtual void setViewportMetaNonUserScalableQuirk(bool);
     virtual void setViewportMetaZeroValuesQuirk(bool);
     virtual void setWebAudioEnabled(bool);
     virtual void setWebGLErrorsToConsoleEnabled(bool);
@@ -192,6 +193,7 @@ public:
     bool perTilePaintingEnabled() const { return m_perTilePaintingEnabled; }
     bool supportDeprecatedTargetDensityDPI() const { return m_supportDeprecatedTargetDensityDPI; }
     bool viewportMetaLayoutSizeQuirk() const { return m_viewportMetaLayoutSizeQuirk; }
+    bool viewportMetaNonUserScalableQuirk() const { return m_viewportMetaNonUserScalableQuirk; }
     int pinchOverlayScrollbarThickness() const { return m_pinchOverlayScrollbarThickness; }
 
 private:
@@ -209,6 +211,10 @@ private:
     // the Android SDK prior to and including version 18. Presumably, this
     // can be removed any time after 2015. See http://crbug.com/277369.
     bool m_viewportMetaLayoutSizeQuirk;
+    // This quirk is to maintain compatibility with Android apps built on
+    // the Android SDK prior to and including version 18. Presumably, this
+    // can be removed any time after 2015. See http://crbug.com/312691.
+    bool m_viewportMetaNonUserScalableQuirk;
     int m_pinchOverlayScrollbarThickness;
 };