Make RenderSVGResource::requestPaintingResource an implementation detail

Source/core/rendering/svg/RenderSVGResource.h

Index: Source/core/rendering/svg/RenderSVGResource.h
diff --git a/Source/core/rendering/svg/RenderSVGResource.h b/Source/core/rendering/svg/RenderSVGResource.h
index 2b822e0305d69e07ce5c110c90dd8c89bd2fae9d..72662d5c407aee5306a811efca5d0b49b0b862c4 100644
--- a/Source/core/rendering/svg/RenderSVGResource.h
+++ b/Source/core/rendering/svg/RenderSVGResource.h
@@ -32,7 +32,6 @@ enum RenderSVGResourceType {
     PatternResourceType,
     LinearGradientResourceType,
     RadialGradientResourceType,
-    SolidColorResourceType,
     FilterResourceType,
     ClipperResourceType
 };
@@ -46,7 +45,6 @@ class GraphicsContext;
 class GraphicsContextStateSaver;
 class RenderObject;
 class RenderStyle;
-class RenderSVGResourceSolidColor;
 
 class SVGPaintServer {
 public:
@@ -79,10 +77,21 @@ public:
 
     virtual RenderSVGResourceType resourceType() const = 0;
 
-    // Helper utilities used in the render tree to access resources used for painting shapes/text (gradients & patterns & solid colors only)
-    // If hasFallback gets set to true, the sharedSolidPaintingResource is set to a fallback color.
-    static RenderSVGResource* requestPaintingResource(RenderSVGResourceMode, const RenderObject&, const RenderStyle*, bool& hasFallback);
-    static RenderSVGResourceSolidColor* sharedSolidPaintingResource();
+    // Helper utilities used in the render tree to access resources used for
+    // painting shapes/text (gradients & patterns & solid colors only).
+    // If |PaintDescription::hasFallback| is true, |PaintDescription::color| is set to a fallback color.
+    struct PaintDescription {

[f(malita), 2014/10/20 14:51:06]

This smells close enough to a paint server to make me wonder why we're not just
building/returning one of those instead.

I think {fill,stroke}Contains() are the only users not turning this into a paint
server immediately, no? Not sure whether returning a fully resolved server is
going to show a perf impact there, but if it does we could add a simplified
hasValidPaintServer() for them.

Is this feasible?

[fs, 2014/10/20 15:20:20]

It's the case you mention and the DRT code. For DRT, the only missing piece is
the id off the element. It's quite possible we could just pass that from the
SVGRenderStyle (since it should be validated already.)

As for hasValidPaintServer, I had that in a previous CL, but ended up
disappearing it... It should be unproblematic to reappear it though. I'll try it
out.

[fs, 2014/10/20 15:52:24]

Oh, and it'll not be possible to tell a fallback color from a regular color.
That doesn't seem like a big issue though (and I'll let the try-bots figure that
out...)

+        PaintDescription() : resource(nullptr), isValid(false), hasFallback(false) { }
+        PaintDescription(Color color) : resource(nullptr), color(color), isValid(true), hasFallback(false) { }
+        PaintDescription(RenderSVGResource* resource) : resource(resource), isValid(true), hasFallback(false) { ASSERT(resource); }
+        PaintDescription(RenderSVGResource* resource, Color fallbackColor) : resource(resource), color(fallbackColor), isValid(true), hasFallback(true) { ASSERT(resource); }
+
+        RenderSVGResource* resource;
+        Color color;
+        bool isValid;
+        bool hasFallback;
+    };
+    static PaintDescription requestPaint(RenderSVGResourceMode, const RenderObject&, const RenderStyle*);
 
     static void markForLayoutAndParentResourceInvalidation(RenderObject*, bool needsLayout = true);
 };