Bug 1106522 (Part 1) - Make imgLoader::SupportImageWithMimeType optionally support image/svg+xml. r=bz

dom/html/HTMLImageElement.cpp

@@ -1103,7 +1103,10 @@ HTMLImageElement::TryCreateResponsiveSelector(nsIContent *aSourceNode,
 
     nsAutoString type;
     if (aSourceNode->GetAttr(kNameSpaceID_None, nsGkAtoms::type, type) &&
-        !imgLoader::SupportImageWithMimeType(NS_ConvertUTF16toUTF8(type).get())) {
+        !imgLoader::SupportImageWithMimeType(
+          NS_ConvertUTF16toUTF8(type).get(),
+          AcceptedMimeTypes::IMAGES_AND_DOCUMENTS)
+        ) {
       return false;
     }
   } else if (aSourceNode->Tag() == nsGkAtoms::img) {

image/src/imgLoader.cpp

@@ -2304,10 +2304,19 @@ nsresult imgLoader::LoadImageWithChannel(nsIChannel *channel, imgINotificationOb
   return rv;
 }
 
-bool imgLoader::SupportImageWithMimeType(const char* aMimeType)
+bool
+imgLoader::SupportImageWithMimeType(const char* aMimeType,
+                                    AcceptedMimeTypes aAccept
+                                      /* = AcceptedMimeTypes::IMAGES */)
 {
   nsAutoCString mimeType(aMimeType);
   ToLowerCase(mimeType);
+
+  if (aAccept == AcceptedMimeTypes::IMAGES_AND_DOCUMENTS &&
+      mimeType.EqualsLiteral("image/svg+xml")) {
+    return true;
+  }
+
   return Image::GetDecoderType(mimeType.get()) != Image::eDecoderType_unknown;
 }
 

image/src/imgLoader.h

@@ -206,6 +206,11 @@ private:
   uint32_t mSize;
 };
 
+MOZ_BEGIN_ENUM_CLASS(AcceptedMimeTypes, uint8_t)
+  IMAGES,
+  IMAGES_AND_DOCUMENTS,
+MOZ_END_ENUM_CLASS(AcceptedMimeTypes)
+
 class imgLoader MOZ_FINAL : public imgILoader,
                             public nsIContentSniffer,
                             public imgICache,
@@ -271,8 +276,22 @@ public:
                                 imgRequestProxy **_retval);
 
   static nsresult GetMimeTypeFromContent(const char* aContents, uint32_t aLength, nsACString& aContentType);
-  // exported for use by mimei.cpp in libxul sdk builds
-  static NS_EXPORT_(bool) SupportImageWithMimeType(const char* aMimeType);
+
+  /**
+   * Returns true if the given mime type may be interpreted as an image.
+   *
+   * Some MIME types may be interpreted as both images and documents. (At the
+   * moment only "image/svg+xml" falls into this category, but there may be more
+   * in the future.) Callers which want this function to return true for such
+   * MIME types should pass AcceptedMimeTypes::IMAGES_AND_DOCUMENTS for @aAccept.
+   *
+   * @param aMimeType The MIME type to evaluate.
+   * @param aAcceptedMimeTypes Which kinds of MIME types to treat as images.
+   */
+  static NS_EXPORT_(bool)
+  SupportImageWithMimeType(const char* aMimeType,
+                           AcceptedMimeTypes aAccept =
+                             AcceptedMimeTypes::IMAGES);
 
   static void GlobalInit(); // for use by the factory
   static void Shutdown(); // for use by the factory