[css-device-adapt] Implemented spec changes.

Source/core/dom/ViewportArguments.cpp

Index: Source/core/dom/ViewportArguments.cpp
diff --git a/Source/core/dom/ViewportArguments.cpp b/Source/core/dom/ViewportArguments.cpp
index 8593f84c5e24c65a599df23b63b1bd621cda4c43..b8125bcd3267a9a2da9ac76e604aa2f7a758504b 100644
--- a/Source/core/dom/ViewportArguments.cpp
+++ b/Source/core/dom/ViewportArguments.cpp
@@ -140,10 +140,10 @@ PageScaleConstraints ViewportArguments::resolve(const FloatSize& initialViewport
         }
 
         if (resultMinWidth != ViewportArguments::ValueAuto || resultMaxWidth != ViewportArguments::ValueAuto)
-            resultWidth = compareIgnoringAuto(resultMinWidth, compareIgnoringAuto(resultMaxWidth, deviceSize.width(), min), max);
+            resultWidth = compareIgnoringAuto(resultMinWidth, compareIgnoringAuto(resultMaxWidth, initialViewportSize.width(), min), max);
 
         if (resultMinHeight != ViewportArguments::ValueAuto || resultMaxHeight != ViewportArguments::ValueAuto)
-            resultHeight = compareIgnoringAuto(resultMinHeight, compareIgnoringAuto(resultMaxHeight, deviceSize.height(), min), max);
+            resultHeight = compareIgnoringAuto(resultMinHeight, compareIgnoringAuto(resultMaxHeight, initialViewportSize.height(), min), max);
 
         if (resultMinZoom != ViewportArguments::ValueAuto && resultMaxZoom != ViewportArguments::ValueAuto)
             resultMaxZoom = max(resultMinZoom, resultMaxZoom);
@@ -151,25 +151,18 @@ PageScaleConstraints ViewportArguments::resolve(const FloatSize& initialViewport
         if (resultZoom != ViewportArguments::ValueAuto)
             resultZoom = compareIgnoringAuto(resultMinZoom, compareIgnoringAuto(resultMaxZoom, resultZoom, min), max);
 
-        if (resultWidth == ViewportArguments::ValueAuto && resultZoom == ViewportArguments::ValueAuto)
-            resultWidth = deviceSize.width();
-
-        if (resultWidth == ViewportArguments::ValueAuto && resultHeight == ViewportArguments::ValueAuto)
-            resultWidth = deviceSize.width() / resultZoom;
+        if (resultWidth == ViewportArguments::ValueAuto && (resultHeight == ViewportArguments::ValueAuto || !initialViewportSize.height()))
+            resultWidth = initialViewportSize.width();
 
         if (resultWidth == ViewportArguments::ValueAuto)
-            resultWidth = resultHeight * deviceSize.width() / deviceSize.height();
-
-        if (resultHeight == ViewportArguments::ValueAuto)
-            resultHeight = resultWidth * deviceSize.height() / deviceSize.width();
+            resultWidth = resultHeight * initialViewportSize.width() / initialViewportSize.height();

[kenneth.r.christiansen, 2013/06/13 13:46:42]

I am a bit afraid that  this might break Android, as initialViewportSize depends
on orientation, where as deviceSize is always given portrait mode.

[Peter Beverloo, 2013/06/28 01:13:51]

Can you please add an ASSERT() to ensure that initialViewportSize.height() > 0? 
The current non-testing code path ensures this elsewhere, but if I have the
following line in a layout test it could cause a divide-by-zero:

internals.configurationForViewport(document, 1, 0, 0, 0, 0);

[rune, 2013/07/03 08:01:52]

Added.
It's ensured also for the configurationForViewport in the if-clause right above,
but it's not that obvious so an ASSERT is warranted.

 
-        if (resultZoom != ViewportArguments::ValueAuto || resultMaxZoom != ViewportArguments::ValueAuto) {
-            resultWidth = compareIgnoringAuto(resultWidth, deviceSize.width() / compareIgnoringAuto(resultZoom, resultMaxZoom, min), max);
-            resultHeight = compareIgnoringAuto(resultHeight, deviceSize.height() / compareIgnoringAuto(resultZoom, resultMaxZoom, min), max);
+        if (resultHeight == ViewportArguments::ValueAuto) {
+            if (!initialViewportSize.width())
+                resultHeight = initialViewportSize.height();
+            else
+                resultHeight = resultWidth * initialViewportSize.height() / initialViewportSize.width();
         }
-
-        resultWidth = max<float>(1, resultWidth);
-        resultHeight = max<float>(1, resultHeight);
     }
 
     if (type != ViewportArguments::CSSDeviceAdaptation && type != ViewportArguments::Implicit) {
@@ -201,9 +194,9 @@ PageScaleConstraints ViewportArguments::resolve(const FloatSize& initialViewport
     result.initialScale = resultZoom;
     if (resultZoom == ViewportArguments::ValueAuto) {
         result.initialScale = initialViewportSize.width() / defaultWidth;
-        if (resultWidth != ViewportArguments::ValueAuto)
+        if (resultWidth != ViewportArguments::ValueAuto && resultWidth > 0)
             result.initialScale = initialViewportSize.width() / resultWidth;
-        if (resultHeight != ViewportArguments::ValueAuto) {
+        if (resultHeight != ViewportArguments::ValueAuto && resultHeight > 0) {
             // if 'auto', the initial-scale will be negative here and thus ignored.
             result.initialScale = max<float>(result.initialScale, initialViewportSize.height() / resultHeight);
         }