Added a method to detect all supported "image/*" MIME types

Since other methods separate supported binary image MIME types from SVG,
where SVG was detected as a "non image type" along with XML, and since I
needed a method to detect MIME types that can be displayed as an image,
I've added such a method.

BUG=398443

Review URL: https://codereview.chromium.org/471913002

Cr-Commit-Position: refs/heads/master@{#291750}

content/child/simple_webmimeregistry_impl.cc

@@ -34,6 +34,16 @@ WebMimeRegistry::SupportsType SimpleWebMimeRegistryImpl::supportsImageMIMEType(
       WebMimeRegistry::IsSupported : WebMimeRegistry::IsNotSupported;
 }
 
+WebMimeRegistry::SupportsType
+    SimpleWebMimeRegistryImpl::supportsImagePrefixedMIMEType(
+    const WebString& mime_type) {
+    std::string ascii_mime_type = ToASCIIOrEmpty(mime_type);
+  return (net::IsSupportedImageMimeType(ascii_mime_type) ||
+          (StartsWithASCII(ascii_mime_type, "image/", true) &&
+           net::IsSupportedNonImageMimeType(ascii_mime_type))) ?
+      WebMimeRegistry::IsSupported : WebMimeRegistry::IsNotSupported;
+}
+
 WebMimeRegistry::SupportsType
     SimpleWebMimeRegistryImpl::supportsJavaScriptMIMEType(
     const WebString& mime_type) {

content/child/simple_webmimeregistry_impl.h

@@ -28,6 +28,8 @@ class CONTENT_EXPORT SimpleWebMimeRegistryImpl :
       const blink::WebString&);
   virtual blink::WebMimeRegistry::SupportsType supportsImageMIMEType(
       const blink::WebString&);
+  virtual blink::WebMimeRegistry::SupportsType supportsImagePrefixedMIMEType(
+      const blink::WebString&);
   virtual blink::WebMimeRegistry::SupportsType supportsJavaScriptMIMEType(
       const blink::WebString&);
   virtual blink::WebMimeRegistry::SupportsType supportsMediaMIMEType(

content/child/simple_webmimeregistry_impl_unittest.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Tests for SimpleWebMimeRegistryImpl.
+
+#include "content/child/simple_webmimeregistry_impl.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/WebKit/public/platform/WebString.h"
+
+TEST(SimpleWebMimeRegistryImpl, mimeTypeTest)
+{
+  content::SimpleWebMimeRegistryImpl registry;
+
+  EXPECT_TRUE(registry.supportsImagePrefixedMIMEType("image/gif"));
+  EXPECT_TRUE(registry.supportsImagePrefixedMIMEType("image/svg+xml"));
+  EXPECT_FALSE(registry.supportsImageMIMEType("image/svg+xml"));
+  EXPECT_TRUE(registry.supportsImageMIMEType("image/gif"));
+}
+

content/content_tests.gypi

@@ -636,6 +636,7 @@
         'child/npapi/plugin_lib_unittest.cc',
         'child/power_monitor_broadcast_source_unittest.cc',
         'child/resource_dispatcher_unittest.cc',
+        'child/simple_webmimeregistry_impl_unittest.cc',
         'child/site_isolation_policy_unittest.cc',
         'child/touch_fling_gesture_curve_unittest.cc',
         'child/web_url_loader_impl_unittest.cc',