added GetStyleContextFor

layout/base/nsIPresShell.h

@@ -37,6 +37,7 @@ class nsIDOMSelection;
 class nsString;
 class nsStringArray;
 class nsICaret;
+class nsIStyleContext;
 
 #define NS_IPRESSHELL_IID     \
 { 0x76e79c60, 0x944e, 0x11d1, \
@@ -147,6 +148,13 @@ public:
   NS_IMETHOD GetPrimaryFrameFor(nsIContent* aContent,
                                 nsIFrame**  aPrimaryFrame) const = 0;
 
+  /** Returns the style context associated with the frame.
+    * Used by code outside of layout that can't use nsIFrame methods to get
+    * the style context directly.
+    */
+  NS_IMETHOD GetStyleContextFor(nsIFrame*         aFrame,
+                                nsIStyleContext** aStyleContext) const = 0;
+
   /**
    * Returns a layout object associated with the primary frame for the content object.
    *

layout/base/nsPresShell.cpp

@@ -272,6 +272,8 @@ public:
   NS_IMETHOD GetPageSequenceFrame(nsIPageSequenceFrame** aResult) const;
   NS_IMETHOD GetPrimaryFrameFor(nsIContent* aContent,
                                 nsIFrame**  aPrimaryFrame) const;
+  NS_IMETHOD GetStyleContextFor(nsIFrame*         aFrame,
+                                nsIStyleContext** aStyleContext) const;
   NS_IMETHOD GetLayoutObjectFor(nsIContent*   aContent,
                                 nsISupports** aResult) const;
   NS_IMETHOD GetPlaceholderFrameFor(nsIFrame*  aFrame,
@@ -1703,6 +1705,15 @@ PresShell::GetPrimaryFrameFor(nsIContent* aContent,
   return NS_OK;
 }
 
+NS_IMETHODIMP 
+PresShell::GetStyleContextFor(nsIFrame*         aFrame,
+                              nsIStyleContext** aStyleContext) const
+{
+  if (!aFrame || !aStyleContext) {
+    return NS_ERROR_NULL_POINTER;
+  }
+  return (aFrame->GetStyleContext(aStyleContext));
+}
 
 NS_IMETHODIMP
 PresShell::GetLayoutObjectFor(nsIContent*   aContent,

layout/base/public/nsIPresShell.h

@@ -37,6 +37,7 @@ class nsIDOMSelection;
 class nsString;
 class nsStringArray;
 class nsICaret;
+class nsIStyleContext;
 
 #define NS_IPRESSHELL_IID     \
 { 0x76e79c60, 0x944e, 0x11d1, \
@@ -147,6 +148,13 @@ public:
   NS_IMETHOD GetPrimaryFrameFor(nsIContent* aContent,
                                 nsIFrame**  aPrimaryFrame) const = 0;
 
+  /** Returns the style context associated with the frame.
+    * Used by code outside of layout that can't use nsIFrame methods to get
+    * the style context directly.
+    */
+  NS_IMETHOD GetStyleContextFor(nsIFrame*         aFrame,
+                                nsIStyleContext** aStyleContext) const = 0;
+
   /**
    * Returns a layout object associated with the primary frame for the content object.
    *

layout/html/base/src/nsPresShell.cpp

@@ -272,6 +272,8 @@ public:
   NS_IMETHOD GetPageSequenceFrame(nsIPageSequenceFrame** aResult) const;
   NS_IMETHOD GetPrimaryFrameFor(nsIContent* aContent,
                                 nsIFrame**  aPrimaryFrame) const;
+  NS_IMETHOD GetStyleContextFor(nsIFrame*         aFrame,
+                                nsIStyleContext** aStyleContext) const;
   NS_IMETHOD GetLayoutObjectFor(nsIContent*   aContent,
                                 nsISupports** aResult) const;
   NS_IMETHOD GetPlaceholderFrameFor(nsIFrame*  aFrame,
@@ -1703,6 +1705,15 @@ PresShell::GetPrimaryFrameFor(nsIContent* aContent,
   return NS_OK;
 }
 
+NS_IMETHODIMP 
+PresShell::GetStyleContextFor(nsIFrame*         aFrame,
+                              nsIStyleContext** aStyleContext) const
+{
+  if (!aFrame || !aStyleContext) {
+    return NS_ERROR_NULL_POINTER;
+  }
+  return (aFrame->GetStyleContext(aStyleContext));
+}
 
 NS_IMETHODIMP
 PresShell::GetLayoutObjectFor(nsIContent*   aContent,