Support content scheme uri for Chrome on Android

Android uses content scheme to store files and ensure permission checks.
For example, the downloaded files are stored as content://downloads/all_downloads/123.
However, chrome currently cannot handle url requests for content uri.
As a result, chrome can save html pages to sdcard, but cannot open it.
This change adds the content scheme support for chrome on android.

BUG=433011

Review URL: https://codereview.chromium.org/739033003

Cr-Commit-Position: refs/heads/master@{#305772}

2 files changed, 3 insertions, 0 deletions

diff --git a/url/url_constants.cc b/url/url_constants.cc
index 9ef0e63..2dc1478 100644
--- a/url/url_constants.cc
+++ b/url/url_constants.cc
@@ -10,6 +10,7 @@ const char kAboutBlankURL[] = "about:blank";
 
 const char kAboutScheme[] = "about";
 const char kBlobScheme[] = "blob";
+const char kContentScheme[] = "content";
 const char kDataScheme[] = "data";
 const char kFileScheme[] = "file";
 const char kFileSystemScheme[] = "filesystem";
diff --git a/url/url_constants.h b/url/url_constants.h
index 3228bbb..c48dafc 100644
--- a/url/url_constants.h
+++ b/url/url_constants.h
@@ -13,6 +13,8 @@ URL_EXPORT extern const char kAboutBlankURL[];
 
 URL_EXPORT extern const char kAboutScheme[];
 URL_EXPORT extern const char kBlobScheme[];
+// The content scheme is specific to Android for identifying a stored file.
+URL_EXPORT extern const char kContentScheme[];
 URL_EXPORT extern const char kDataScheme[];
 URL_EXPORT extern const char kFileScheme[];
 URL_EXPORT extern const char kFileSystemScheme[];