3 files changed, 34 insertions, 3 deletions
diff --git a/chrome/browser/dom_ui/chrome_url_data_manager.cc b/chrome/browser/dom_ui/chrome_url_data_manager.cc
index 4eb7b9f..1102b87 100644
--- a/chrome/browser/dom_ui/chrome_url_data_manager.cc
+++ b/chrome/browser/dom_ui/chrome_url_data_manager.cc
@@ -52,6 +52,10 @@ class URLRequestChromeJob : public URLRequestJob {
   // for us.
   void DataAvailable(RefCountedBytes* bytes);
 
+  void SetMimeType(const std::string& mime_type) {
+    mime_type_ = mime_type;
+  }
+
  private:
   // Helper for Start(), to let us start asynchronously.
   // (This pattern is shared by most URLRequestJob implementations.)
@@ -71,6 +75,7 @@ class URLRequestChromeJob : public URLRequestJob {
   // we're reading into.
   char* pending_buf_;
   int pending_buf_size_;
+  std::string mime_type_;
 
   DISALLOW_EVIL_CONSTRUCTORS(URLRequestChromeJob);
 };
@@ -187,6 +192,11 @@ bool ChromeURLDataManager::StartRequest(const GURL& url,
   RequestID request_id = next_request_id_++;
   pending_requests_.insert(std::make_pair(request_id, job));
 
+  // TODO(eroman): would be nicer if the mimetype were set at the same time
+  // as the data blob. For now do it here, since NotifyHeadersComplete() is
+  // going to get called once we return.
+  job->SetMimeType(source->GetMimeType(path));
+
   // Forward along the request to the data source.
   source->message_loop()->PostTask(FROM_HERE,
       NewRunnableMethod(source, &DataSource::StartDataRequest,
@@ -258,9 +268,8 @@ void URLRequestChromeJob::Kill() {
 }
 
 bool URLRequestChromeJob::GetMimeType(std::string* mime_type) {
-  // Rely on MIME sniffing to simplify the logic here.
-  *mime_type = "text/html";
-  return true;
+  *mime_type = mime_type_;
+  return !mime_type_.empty();
 }
 
 void URLRequestChromeJob::DataAvailable(RefCountedBytes* bytes) {
diff --git a/chrome/browser/dom_ui/chrome_url_data_manager.h b/chrome/browser/dom_ui/chrome_url_data_manager.h
index a7f07f2..895ff46 100644
--- a/chrome/browser/dom_ui/chrome_url_data_manager.h
+++ b/chrome/browser/dom_ui/chrome_url_data_manager.h
@@ -48,6 +48,10 @@ class ChromeURLDataManager {
     // not be satisfied.
     virtual void StartDataRequest(const std::string& path, int request_id) = 0;
 
+    // Return the mimetype that should be sent with this response, or empty
+    // string to specify no mime type.
+    virtual std::string GetMimeType(const std::string& path) const = 0;
+
     // Report that a request has resulted in the data |bytes|.
     // If the request can't be satisfied, pass NULL for |bytes| to indicate
     // the request is over.
diff --git a/chrome/browser/dom_ui/new_tab_ui.h b/chrome/browser/dom_ui/new_tab_ui.h
index aab91f2..ed31cde 100644
--- a/chrome/browser/dom_ui/new_tab_ui.h
+++ b/chrome/browser/dom_ui/new_tab_ui.h
@@ -36,6 +36,10 @@ class NewTabHTMLSource : public ChromeURLDataManager::DataSource {
   // the path we registered.
   virtual void StartDataRequest(const std::string& path, int request_id);
 
+  virtual std::string GetMimeType(const std::string&) const {
+    return "text/html";
+  }
+
   // Setters and getters for first_view.
   static void set_first_view(bool first_view) { first_view_ = first_view; }
   static bool first_view() { return first_view_; }
@@ -57,6 +61,10 @@ class IncognitoTabHTMLSource : public ChromeURLDataManager::DataSource {
   // the path we registered.
   virtual void StartDataRequest(const std::string& path, int request_id);
 
+  virtual std::string GetMimeType(const std::string&) const {
+    return "text/html";
+  }
+
  private:
   DISALLOW_EVIL_CONSTRUCTORS(IncognitoTabHTMLSource);
 };
@@ -71,6 +79,11 @@ class ThumbnailSource : public ChromeURLDataManager::DataSource {
   // the path we registered.
   virtual void StartDataRequest(const std::string& path, int request_id);
 
+  virtual std::string GetMimeType(const std::string&) const {
+    // Rely on image decoder inferring the correct type.
+    return std::string();
+  }
+
   // Called when thumbnail data is available from the history backend.
   void OnThumbnailDataAvailable(
       HistoryService::Handle request_handle,
@@ -97,6 +110,11 @@ class FavIconSource : public ChromeURLDataManager::DataSource {
   // the path we registered.
   virtual void StartDataRequest(const std::string& path, int request_id);
 
+  virtual std::string GetMimeType(const std::string&) const {
+    // Rely on image decoder inferring the correct type.
+    return std::string();
+  }
+
   // Called when favicon data is available from the history backend.
   void OnFavIconDataAvailable(
       HistoryService::Handle request_handle,