[AiS] Add prefetching for Answers images.

BUG=380916

R=pkasting@chromium.org
TBR=sky@chromium.org

Review URL: https://codereview.chromium.org/314013003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@278653 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/autocomplete/base_search_provider.cc

@@ -13,6 +13,8 @@
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/autocomplete/autocomplete_provider_listener.h"
+#include "chrome/browser/bitmap_fetcher/bitmap_fetcher_service.h"
+#include "chrome/browser/bitmap_fetcher/bitmap_fetcher_service_factory.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/omnibox/omnibox_field_trial.h"
@@ -924,6 +926,7 @@ bool BaseSearchProvider::ParseSuggestResults(const base::Value& root_val,
           const base::DictionaryValue* answer_json = NULL;
           if (suggestion_detail->GetDictionary("ansa", &answer_json)) {
             match_type = AutocompleteMatchType::SEARCH_SUGGEST_ANSWER;
+            PrefetchAnswersImages(answer_json);
             std::string contents;
             base::JSONWriter::Write(answer_json, &contents);
             answer_contents = base::UTF8ToUTF16(contents);
@@ -946,6 +949,33 @@ bool BaseSearchProvider::ParseSuggestResults(const base::Value& root_val,
   return true;
 }
 
+void BaseSearchProvider::PrefetchAnswersImages(
+    const base::DictionaryValue* answer_json) {
+  DCHECK(answer_json);
+  const base::ListValue* lines = NULL;
+  answer_json->GetList("l", &lines);
+  if (!lines || lines->GetSize() == 0)
+    return;
+
+  BitmapFetcherService* image_service =
+      BitmapFetcherServiceFactory::GetForBrowserContext(profile_);
+  DCHECK(image_service);
+
+  for (size_t line = 0; line < lines->GetSize(); ++line) {
+    const base::DictionaryValue* imageLine = NULL;
+    lines->GetDictionary(line, &imageLine);
+    if (!imageLine)
+      continue;
+    const base::DictionaryValue* imageData = NULL;
+    imageLine->GetDictionary("i", &imageData);
+    if (!imageData)
+      continue;
+    std::string imageUrl;
+    imageData->GetString("d", &imageUrl);
+    image_service->Prefetch(GURL(imageUrl));
+  }
+}
+
 void BaseSearchProvider::SortResults(bool is_keyword,
                                      const base::ListValue* relevances,
                                      Results* results) {

chrome/browser/autocomplete/base_search_provider.h

@@ -28,6 +28,7 @@ class SuggestionDeletionHandler;
 class TemplateURL;
 
 namespace base {
+class DictionaryValue;
 class ListValue;
 class Value;
 }
@@ -434,6 +435,9 @@ class BaseSearchProvider : public AutocompleteProvider,
                            bool is_keyword_result,
                            Results* results);
 
+  // Prefetches any images in Answers results.
+  void PrefetchAnswersImages(const base::DictionaryValue* answers_json);
+
   // Called at the end of ParseSuggestResults to rank the |results|.
   virtual void SortResults(bool is_keyword,
                            const base::ListValue* relevances,

chrome/browser/bitmap_fetcher/bitmap_fetcher_service.cc

@@ -114,6 +114,7 @@ BitmapFetcherService::RequestId BitmapFetcherService::RequestImage(
 }
 
 void BitmapFetcherService::Prefetch(const GURL& url) {
+  if (url.is_valid())
     EnsureFetcherForUrl(url);
 }