[Image Fetcher] Add data url support

Bug: 1015174
Change-Id: I356619e74745a31ebd0aef46f64977a025dd099b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2078978
Commit-Queue: Brandon Wylie <wylieb@chromium.org>
Reviewed-by: Sky Malice <skym@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746143}

components/image_fetcher/core/image_data_fetcher.cc

@@ -7,7 +7,9 @@
 #include <utility>
 
 #include "base/bind.h"
+#include "base/task/post_task.h"
 #include "components/image_fetcher/core/image_fetcher_metrics_reporter.h"
+#include "net/base/data_url.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_response_headers.h"
 #include "net/http/http_status_code.h"
@@ -16,6 +18,7 @@
 #include "services/network/public/cpp/shared_url_loader_factory.h"
 #include "services/network/public/cpp/simple_url_loader.h"
 #include "url/gurl.h"
+#include "url/url_constants.h"
 
 namespace {
 
@@ -103,6 +106,21 @@ void ImageDataFetcher::FetchImageData(
     net::URLRequest::ReferrerPolicy referrer_policy,
     bool send_cookies) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+
+  // Handle data urls explicitly since SimpleURLLoader doesn't.
+  if (image_url.SchemeIs(url::kDataScheme)) {
+    std::string mime_type, charset, data;
+    if (!net::DataURL::Parse(image_url, &mime_type, &charset, &data)) {
+      DVLOG(0) << "Failed to parse data url";
+    }
+
+    // Post a task to maintain our guarantee that the call won't be called
+    // synchronously.
+    base::PostTask(FROM_HERE, BindOnce(std::move(callback), std::move(data),
+                                       RequestMetadata()));
+    return;
+  }
+
   auto request = std::make_unique<network::ResourceRequest>();
   request->url = image_url;
   request->referrer_policy = referrer_policy;

components/image_fetcher/core/image_data_fetcher.h

@@ -42,7 +42,8 @@ class ImageDataFetcher {
 
   // Fetches the raw image bytes from the given |image_url| and calls the given
   // |callback|. The callback is run even if fetching the URL fails. In case
-  // of an error an empty string is passed to the callback.
+  // of an error an empty string is passed to the callback. Won't return
+  // synchronously.
   void FetchImageData(const GURL& image_url,
                       ImageDataFetcherCallback callback,
                       ImageFetcherParams params,

components/image_fetcher/core/image_data_fetcher_unittest.cc

@@ -6,6 +6,7 @@
 
 #include <memory>
 
+#include "base/base64.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/macros.h"
@@ -59,7 +60,7 @@ class ImageDataFetcherTest : public testing::Test {
                void(const std::string&, const RequestMetadata&));
 
  protected:
-  base::test::SingleThreadTaskEnvironment task_environment_;
+  base::test::TaskEnvironment task_environment_;
   base::HistogramTester histogram_tester_;
 
   network::TestURLLoaderFactory test_url_loader_factory_;
@@ -108,6 +109,25 @@ TEST_F(ImageDataFetcherTest, FetchImageData) {
   histogram_tester().ExpectBucketCount(std::string(kHistogramName), 200, 1);
 }
 
+TEST_F(ImageDataFetcherTest, FetchImageDataWithDataUrl) {
+  std::string data =
+      "iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAYAAABytg0kAAAAFElEQVQYlWNk+M/"
+      "wn4GBgYGJAQoAHhgCAh6X4CYAAAAASUVORK5CYII=";
+  std::string data_url = "data:image/png;base64," + data;
+
+  image_data_fetcher_.FetchImageData(
+      GURL(data_url),
+      base::BindOnce(&ImageDataFetcherTest::OnImageDataFetched,
+                     base::Unretained(this)),
+      ImageFetcherParams(TRAFFIC_ANNOTATION_FOR_TESTS, kTestUmaClientName));
+
+  RequestMetadata expected_metadata;
+  std::string expected;
+  base::Base64Decode(data, &expected);
+  EXPECT_CALL(*this, OnImageDataFetched(expected, expected_metadata));
+  base::RunLoop().RunUntilIdle();
+}
+
 TEST_F(ImageDataFetcherTest, FetchImageDataTrafficAnnotationOnly) {
   std::string content = kURLResponseData;