Add LogoTracker to fetch search providers' logos.

The LogoTracker keeps track of the logo for a search provider. The logo
is downloaded, cached on disk, and periodically revalidated.

This code lives inside a component (search_provider_logos) so it can be
used on both Android and iOS.

BUG=178922
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=267314

Review URL: https://codereview.chromium.org/162373002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@267349 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 93 insertions, 0 deletions

diff --git a/components/search_provider_logos/google_logo_api.cc b/components/search_provider_logos/google_logo_api.cc
new file mode 100644
index 0000000..9a855cb
--- /dev/null
+++ b/components/search_provider_logos/google_logo_api.cc
@@ -0,0 +1,93 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/search_provider_logos/google_logo_api.h"
+
+#include "base/base64.h"
+#include "base/json/json_reader.h"
+#include "base/memory/ref_counted_memory.h"
+#include "base/strings/string_util.h"
+#include "base/values.h"
+#include "net/base/url_util.h"
+
+namespace search_provider_logos {
+
+namespace {
+const char kResponsePreamble[] = ")]}'";
+}
+
+GURL GoogleAppendFingerprintToLogoURL(const GURL& logo_url,
+                                      const std::string& fingerprint) {
+  return net::AppendQueryParameter(logo_url, "async", "es_dfp:" + fingerprint);
+}
+
+scoped_ptr<EncodedLogo> GoogleParseLogoResponse(
+    const scoped_ptr<std::string>& response,
+    base::Time response_time) {
+  // Google doodles are sent as JSON with a prefix. Example:
+  //   )]}' {"update":{"logo":{
+  //     "data": "/9j/4QAYRXhpZgAASUkqAAgAAAAAAAAAAAAAAP/...",
+  //     "mime_type": "image/png",
+  //     "fingerprint": "db063e32",
+  //     "target": "http://www.google.com.au/search?q=Wilbur+Christiansen",
+  //     "alt": "Wilbur Christiansen's Birthday"
+  //     "time_to_live": 1389304799
+  //   }}}
+
+  // The response may start with )]}'. Ignore this.
+  base::StringPiece response_sp(*response);
+  if (response_sp.starts_with(kResponsePreamble))
+    response_sp.remove_prefix(strlen(kResponsePreamble));
+
+  scoped_ptr<base::Value> value(base::JSONReader::Read(response_sp));
+  if (!value.get())
+    return scoped_ptr<EncodedLogo>();
+
+  // The important data lives inside several nested dictionaries:
+  // {"update": {"logo": { "mime_type": ..., etc } } }
+  const base::DictionaryValue* outer_dict;
+  if (!value->GetAsDictionary(&outer_dict))
+    return scoped_ptr<EncodedLogo>();
+  const base::DictionaryValue* update_dict;
+  if (!outer_dict->GetDictionary("update", &update_dict))
+    return scoped_ptr<EncodedLogo>();
+  const base::DictionaryValue* logo_dict;
+  if (!update_dict->GetDictionary("logo", &logo_dict))
+    return scoped_ptr<EncodedLogo>();
+
+  scoped_ptr<EncodedLogo> logo(new EncodedLogo());
+
+  std::string encoded_image_base64;
+  if (logo_dict->GetString("data", &encoded_image_base64)) {
+    // Data is optional, since we may be revalidating a cached logo.
+    base::RefCountedString* encoded_image_string = new base::RefCountedString();
+    if (!base::Base64Decode(encoded_image_base64,
+                            &encoded_image_string->data()))
+      return scoped_ptr<EncodedLogo>();
+    logo->encoded_image = encoded_image_string;
+    if (!logo_dict->GetString("mime_type", &logo->metadata.mime_type))
+      return scoped_ptr<EncodedLogo>();
+  }
+
+  // Don't check return values since these fields are optional.
+  logo_dict->GetString("target", &logo->metadata.on_click_url);
+  logo_dict->GetString("fingerprint", &logo->metadata.fingerprint);
+  logo_dict->GetString("alt", &logo->metadata.alt_text);
+
+  base::TimeDelta time_to_live;
+  int time_to_live_ms;
+  if (logo_dict->GetInteger("time_to_live", &time_to_live_ms)) {
+    time_to_live = base::TimeDelta::FromMilliseconds(
+        std::min(static_cast<int64>(time_to_live_ms), kMaxTimeToLiveMS));
+    logo->metadata.can_show_after_expiration = false;
+  } else {
+    time_to_live = base::TimeDelta::FromMilliseconds(kMaxTimeToLiveMS);
+    logo->metadata.can_show_after_expiration = true;
+  }
+  logo->metadata.expiration_time = response_time + time_to_live;
+
+  return logo.Pass();
+}
+
+}  // namespace search_provider_logos