Add Settings::deviceScaleAdjustment.

Source/core/page/Settings.cpp

Index: Source/core/page/Settings.cpp
diff --git a/Source/core/page/Settings.cpp b/Source/core/page/Settings.cpp
index 3bde44c93c2bbe2bbf28ffc5af339883aee439f3..abbd79cf15b151184041d6fa29ae53a134cc8f16 100644
--- a/Source/core/page/Settings.cpp
+++ b/Source/core/page/Settings.cpp
@@ -120,6 +120,7 @@ Settings::Settings(Page* page)
 #else
     , m_textAutosizingEnabled(false)
 #endif
+    , m_deviceScaleAdjustment(1.0f)

[pdr., 2013/10/30 04:53:08]

I think you'll need to move this above m_textAutosizingEnabled to make the clang
build happy.

error: field 'm_textAutosizingEnabled' will be initialized after field
'm_deviceScaleAdjustment'.

[skobes, 2013/10/30 17:35:51]

Done.

     , m_useWideViewport(true)
     , m_loadWithOverviewMode(true)
     SETTINGS_INITIALIZER_LIST
@@ -258,10 +259,8 @@ void Settings::setLoadWithOverviewMode(bool loadWithOverviewMode)
         m_page->chrome().dispatchViewportPropertiesDidChange(m_page->mainFrame()->document()->viewportDescription());
 }
 
-void Settings::setTextAutosizingFontScaleFactor(float fontScaleFactor)
+void Settings::recalculateTextAutosizingMultipliers()
 {
-    m_textAutosizingFontScaleFactor = fontScaleFactor;
-
     // FIXME: I wonder if this needs to traverse frames like in WebViewImpl::resize, or whether there is only one document per Settings instance?
     for (Frame* frame = m_page->mainFrame(); frame; frame = frame->tree().traverseNext())
         frame->document()->textAutosizer()->recalculateMultipliers();
@@ -269,6 +268,18 @@ void Settings::setTextAutosizingFontScaleFactor(float fontScaleFactor)
     m_page->setNeedsRecalcStyleInAllFrames();
 }
 
+void Settings::setTextAutosizingFontScaleFactor(float fontScaleFactor)
+{
+    m_textAutosizingFontScaleFactor = fontScaleFactor;
+    recalculateTextAutosizingMultipliers();
+}
+
+void Settings::setDeviceScaleAdjustment(float deviceScaleAdjustment)

[pdr., 2013/10/30 04:53:08]

In plumbing this through for the inspector side I found they use "device scale"
in place of DPR. It may be cleaner to call this "setDeviceFontScaleAdjustment",
but this is certainly optional.

[skobes, 2013/10/30 17:35:51]

I tried to make the name agnostic as to where it is applied... today it is on
the font scale factor but in the future it may be used to adjust layout width or
DPR instead.

+{
+    m_deviceScaleAdjustment = deviceScaleAdjustment;
+    recalculateTextAutosizingMultipliers();
+}
+
 void Settings::setMediaTypeOverride(const String& mediaTypeOverride)
 {
     if (m_mediaTypeOverride == mediaTypeOverride)