Add DebugInfo to DistilledPageProto.

Adds a DebugInfo message to the DistilledPageProto. The data for this message
is copied from the DomDistillerResult proto DebugInfo.

For now, only a field for the distiller log exists.

Depends on https://codereview.chromium.org/493853006/

BUG=409274

Review URL: https://codereview.chromium.org/504263002

Cr-Commit-Position: refs/heads/master@{#293205}

components/dom_distiller/core/distiller.cc

@@ -155,6 +155,11 @@ void DistillerImpl::OnPageDistillationFinished(
       page_data->distilled_page_proto->data.set_html(
           distiller_result->distilled_content().html());
     }
+    if (distiller_result->has_debug_info() &&
+        distiller_result->debug_info().has_log()) {
+      page_data->distilled_page_proto->data.mutable_debug_info()->set_log(
+          distiller_result->debug_info().log());
+    }
 
     if (distiller_result->has_pagination_info()) {
       proto::PaginationInfo pagination_info =

components/dom_distiller/core/distiller_unittest.cc

@@ -45,6 +45,7 @@ const size_t kTotalImages = 2;
 const char* kImageURLs[kTotalImages] = {"http://a.com/img1.jpg",
                                         "http://a.com/img2.jpg"};
 const char* kImageData[kTotalImages] = {"abcde", "12345"};
+const char kDebugLog[] = "Debug Log";
 
 const string GetImageName(int page_num, int image_num) {
   return base::IntToString(page_num) + "_" + base::IntToString(image_num);
@@ -341,6 +342,20 @@ TEST_F(DistillerTest, DistillPage) {
   EXPECT_EQ(kURL, first_page.url());
 }
 
+TEST_F(DistillerTest, DistillPageWithDebugInfo) {
+  base::MessageLoopForUI loop;
+  DomDistillerResult dd_result;
+  dd_result.mutable_debug_info()->set_log(kDebugLog);
+  scoped_ptr<base::Value> result =
+      dom_distiller::proto::json::DomDistillerResult::WriteToValue(dd_result);
+  distiller_.reset(
+      new DistillerImpl(url_fetcher_factory_, DomDistillerOptions()));
+  DistillPage(kURL, CreateMockDistillerPage(result.get(), GURL(kURL)).Pass());
+  base::MessageLoop::current()->RunUntilIdle();
+  const DistilledPageProto& first_page = article_proto_->pages(0);
+  EXPECT_EQ(kDebugLog, first_page.debug_info().log());
+}
+
 TEST_F(DistillerTest, DistillPageWithImages) {
   base::MessageLoopForUI loop;
   vector<int> image_indices;

components/dom_distiller/core/proto/distilled_page.proto

@@ -31,4 +31,12 @@ message DistilledPageProto {
 
   // Title for the current page.
   optional string title = 5;
-}
+
\ No newline at end of file
+  message DebugInfo {
+    // Contains the log from the JS distiller.
+    optional string log = 1;
+  }
+
+  // Debug information about this page.
+  optional DebugInfo debug_info = 6;
+}

components/dom_distiller/standalone/content_extractor.cc

@@ -143,6 +143,8 @@ std::string GetReadableArticleString(
     output << "Page " << i << std::endl;
     output << "URL: " << page.url() << std::endl;
     output << "Content: " << page.html() << std::endl;
+    if (page.has_debug_info() && page.debug_info().has_log())
+      output << "Log: " << page.debug_info().log() << std::endl;
   }
   return output.str();
 }