Update MimeSniffingResourceHandler tests to use MockResourceLoader.

content/browser/loader/mock_resource_loader.cc

Index: content/browser/loader/mock_resource_loader.cc
diff --git a/content/browser/loader/mock_resource_loader.cc b/content/browser/loader/mock_resource_loader.cc
index 8be87a46ad775887c3ec03b40809f182561ba49c..d211f38e4be646eaacd1c5ff04a382b24b50600c 100644
--- a/content/browser/loader/mock_resource_loader.cc
+++ b/content/browser/loader/mock_resource_loader.cc
@@ -35,6 +35,9 @@ MockResourceLoader::Status MockResourceLoader::OnWillStart(const GURL& url) {
   EXPECT_TRUE(status_ == Status::CALLING_HANDLER ||
               (result == false && status_ == Status::CANCELED));
   if (!result) {
+    // In the case of double-cancels, keep the old error code.
+    if (status_ != Status::CANCELED)
+      error_code_ = net::ERR_ABORTED;
     status_ = Status::CANCELED;
   } else if (defer) {
     status_ = Status::CALLBACK_PENDING;
@@ -58,6 +61,9 @@ MockResourceLoader::Status MockResourceLoader::OnRequestRedirected(
   EXPECT_TRUE(status_ == Status::CALLING_HANDLER ||
               (result == false && status_ == Status::CANCELED));
   if (!result) {
+    // In the case of double-cancels, keep the old error code.
+    if (status_ != Status::CANCELED)
+      error_code_ = net::ERR_ABORTED;
     status_ = Status::CANCELED;
   } else if (defer) {
     status_ = Status::CALLBACK_PENDING;
@@ -79,6 +85,9 @@ MockResourceLoader::Status MockResourceLoader::OnResponseStarted(
   EXPECT_TRUE(status_ == Status::CALLING_HANDLER ||
               (result == false && status_ == Status::CANCELED));
   if (!result) {
+    // In the case of double-cancels, keep the old error code.
+    if (status_ != Status::CANCELED)
+      error_code_ = net::ERR_ABORTED;
     status_ = Status::CANCELED;
   } else if (defer) {
     status_ = Status::CALLBACK_PENDING;
@@ -105,6 +114,7 @@ MockResourceLoader::Status MockResourceLoader::OnWillRead(int min_size) {
     EXPECT_EQ(0, io_buffer_size_);
     EXPECT_FALSE(io_buffer_);
     status_ = Status::CANCELED;
+    error_code_ = net::ERR_ABORTED;
   } else {
     EXPECT_LE(min_size, io_buffer_size_);
     EXPECT_LT(0, io_buffer_size_);
@@ -132,6 +142,9 @@ MockResourceLoader::Status MockResourceLoader::OnReadCompleted(
   EXPECT_TRUE(status_ == Status::CALLING_HANDLER ||
               (result == false && status_ == Status::CANCELED));
   if (!result) {
+    // In the case of double-cancels, keep the old error code.
+    if (status_ != Status::CANCELED)
+      error_code_ = net::ERR_ABORTED;
     status_ = Status::CANCELED;
   } else if (defer) {
     status_ = Status::CALLBACK_PENDING;