Reflow for screen size change when font.size.inflation.minTwips is set. (Bug 747231, patch 4) r=roc

--HG--
extra : transplant_source : %B2c%F2%B9%E0%1DL%DD%AF%A2%842R%F3%BB%60R%1B%9EI

dom/base/nsDOMWindowUtils.cpp

@@ -78,6 +78,9 @@
 #include "nsDOMFile.h"
 #include "BasicLayers.h"
 #include "nsTArrayHelpers.h"
+#include "nsIDocShell.h"
+#include "nsIContentViewer.h"
+#include "nsIMarkupDocumentViewer.h"
 
 #if defined(MOZ_X11) && defined(MOZ_WIDGET_GTK2)
 #include <gdk/gdk.h>
@@ -283,6 +286,40 @@ static void DestroyNsRect(void* aObject, nsIAtom* aPropertyName,
   delete rect;
 }
 
+static void
+MaybeReflowForInflationScreenWidthChange(nsPresContext *aPresContext)
+{
+  if (aPresContext &&
+      nsLayoutUtils::FontSizeInflationEnabled(aPresContext) &&
+      nsLayoutUtils::FontSizeInflationMinTwips() != 0) {
+    bool changed;
+    aPresContext->ScreenWidthInchesForFontInflation(&changed);
+    if (changed) {
+      nsCOMPtr<nsISupports> container = aPresContext->GetContainer();
+      nsCOMPtr<nsIDocShell> docShell = do_QueryInterface(container);
+      if (docShell) {
+        nsCOMPtr<nsIContentViewer> cv;
+        docShell->GetContentViewer(getter_AddRefs(cv));
+        nsCOMPtr<nsIMarkupDocumentViewer> mudv = do_QueryInterface(cv);
+        if (mudv) {
+          nsTArray<nsCOMPtr<nsIMarkupDocumentViewer> > array;
+          mudv->AppendSubtree(array);
+          for (PRUint32 i = 0, iEnd = array.Length(); i < iEnd; ++i) {
+            nsCOMPtr<nsIPresShell> shell;
+            nsCOMPtr<nsIContentViewer> cv = do_QueryInterface(array[i]);
+            cv->GetPresShell(getter_AddRefs(shell));
+            nsIFrame *rootFrame = shell->GetRootFrame();
+            if (rootFrame) {
+              shell->FrameNeedsReflow(rootFrame, nsIPresShell::eResize,
+                                      NS_FRAME_IS_DIRTY);
+            }
+          }
+        }
+      }
+    }
+  }
+}
+
 NS_IMETHODIMP
 nsDOMWindowUtils::SetDisplayPortForElement(float aXPx, float aYPx,
                                            float aWidthPx, float aHeightPx,
@@ -331,6 +368,14 @@ nsDOMWindowUtils::SetDisplayPortForElement(float aXPx, float aYPx,
       // We are setting a root displayport for a document.
       // The pres shell needs a special flag set.
       presShell->SetIgnoreViewportScrolling(true);
+
+      // When the "font.size.inflation.minTwips" preference is set, the
+      // layout depends on the size of the screen.  Since when the size
+      // of the screen changes, the root displayport also changes, we
+      // hook in the needed updates here rather than adding a
+      // separate notification just for this change.
+      nsPresContext* presContext = GetPresContext();
+      MaybeReflowForInflationScreenWidthChange(presContext);
     }
   }
 

layout/base/nsLayoutUtils.cpp

@@ -132,8 +132,8 @@ bool nsLayoutUtils::gPreventAssertInCompareTreePosition = false;
 typedef gfxPattern::GraphicsFilter GraphicsFilter;
 typedef FrameMetrics::ViewID ViewID;
 
-static PRUint32 sFontSizeInflationEmPerLine;
-static PRUint32 sFontSizeInflationMinTwips;
+/* static */ PRUint32 nsLayoutUtils::sFontSizeInflationEmPerLine;
+/* static */ PRUint32 nsLayoutUtils::sFontSizeInflationMinTwips;
 /* static */ PRUint32 nsLayoutUtils::sFontSizeInflationLineThreshold;
 
 static ViewID sScrollIdCounter = FrameMetrics::START_SCROLL_ID;
@@ -4671,7 +4671,9 @@ nsReflowFrameRunnable::Run()
 static nscoord
 MinimumFontSizeFor(nsPresContext* aPresContext, nscoord aContainerWidth)
 {
-  if (sFontSizeInflationEmPerLine == 0 && sFontSizeInflationMinTwips == 0) {
+  PRUint32 emPerLine = nsLayoutUtils::FontSizeInflationEmPerLine();
+  PRUint32 minTwips = nsLayoutUtils::FontSizeInflationMinTwips();
+  if (emPerLine == 0 && minTwips == 0) {
     return 0;
   }
 
@@ -4680,17 +4682,17 @@ MinimumFontSizeFor(nsPresContext* aPresContext, nscoord aContainerWidth)
   nscoord effectiveContainerWidth = NS_MIN(iFrameWidth, aContainerWidth);
 
   nscoord byLine = 0, byInch = 0;
-  if (sFontSizeInflationEmPerLine != 0) {
-    byLine = effectiveContainerWidth / sFontSizeInflationEmPerLine;
+  if (emPerLine != 0) {
+    byLine = effectiveContainerWidth / emPerLine;
   }
-  if (sFontSizeInflationMinTwips != 0) {
+  if (minTwips != 0) {
     // REVIEW: Is this giving us app units and sizes *not* counting
     // viewport scaling?
     float deviceWidthInches =
       aPresContext->ScreenWidthInchesForFontInflation();
     byInch = NSToCoordRound(effectiveContainerWidth /
                             (deviceWidthInches * 1440 /
-                             sFontSizeInflationMinTwips ));
+                             minTwips ));
   }
   return NS_MAX(byLine, byInch);
 }

layout/base/nsLayoutUtils.h

@@ -1567,6 +1567,22 @@ public:
 
   static bool FontSizeInflationEnabled(nsPresContext *aPresContext);
 
+  /**
+   * See comment above "font.size.inflation.emPerLine" in
+   * modules/libpref/src/init/all.js .
+   */
+  static PRUint32 FontSizeInflationEmPerLine() {
+    return sFontSizeInflationEmPerLine;
+  }
+
+  /**
+   * See comment above "font.size.inflation.minTwips" in
+   * modules/libpref/src/init/all.js .
+   */
+  static PRUint32 FontSizeInflationMinTwips() {
+    return sFontSizeInflationMinTwips;
+  }
+
   /**
    * See comment above "font.size.inflation.lineThreshold" in
    * modules/libpref/src/init/all.js .
@@ -1655,6 +1671,8 @@ public:
 #endif
 
 private:
+  static PRUint32 sFontSizeInflationEmPerLine;
+  static PRUint32 sFontSizeInflationMinTwips;
   static PRUint32 sFontSizeInflationLineThreshold;
 };