[Android] Add API for specifying a charset for data Urls.

content/public/android/java/src/org/chromium/content/browser/LoadUrlParams.java

Index: content/public/android/java/src/org/chromium/content/browser/LoadUrlParams.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/LoadUrlParams.java b/content/public/android/java/src/org/chromium/content/browser/LoadUrlParams.java
index 24d153f92ea367b27f42a1b6bdaa371c76a4380d..696dbcdc5d8e033f1095aabbace511a4254ed5e9 100644
--- a/content/public/android/java/src/org/chromium/content/browser/LoadUrlParams.java
+++ b/content/public/android/java/src/org/chromium/content/browser/LoadUrlParams.java
@@ -29,6 +29,10 @@ public class LoadUrlParams {
     public static int UA_OVERRIDE_FALSE;
     public static int UA_OVERRIDE_TRUE;
 
+    // The default character encoding for data URLs as defined in
+    // RFC 2397.
+    private static final String DATA_URL_DEFAULT_CHARSET = "US-ASCII";
+
     // Fields with counterparts in NavigationController::LoadURLParams.
     // Package private so that ContentViewCore.loadUrl can pass them down to
     // native code. Should not be accessed directly anywhere else outside of
@@ -57,15 +61,29 @@ public class LoadUrlParams {
     }
 
     /**
+     * Helper method to create a LoadUrlParams object for data url. Defaults
+     * to US-ASCII charset, as per RFC2397.
+     * @param data Data to be loaded.
+     * @param mimeType Mime type of the data.
+     * @param isBase64Encoded True if the data is encoded in Base 64 format.
+     */
+    public static LoadUrlParams createLoadDataParams(
+        String data, String mimeType, boolean isBase64Encoded) {
+        return createLoadDataParams(data, mimeType, isBase64Encoded, DATA_URL_DEFAULT_CHARSET);
+    }
+
+    /**
      * Helper method to create a LoadUrlParams object for data url.
      * @param data Data to be loaded.
      * @param mimeType Mime type of the data.
      * @param isBase64Encoded True if the data is encoded in Base 64 format.
+     * @param charset The character set for the data.
      */
     public static LoadUrlParams createLoadDataParams(
-            String data, String mimeType, boolean isBase64Encoded) {
+            String data, String mimeType, boolean isBase64Encoded, String charset) {
         StringBuilder dataUrl = new StringBuilder("data:");
         dataUrl.append(mimeType);
+        dataUrl.append(";charset=" + charset);

[joth, 2012/12/14 18:02:51]

-AIUI the charset is spurious if the mimetype is not text/* -- what would it
mean to have a shift-jis charset JPEG or UCS-32 .exe ? (if the payload is base64
encoded, the charset applies to the decoded form, I believe. the base64  encoded
form is unavoidably us-ascii.)
-the receiver defaults to US-ASCII so we can always omit it in that case too,
but it doesn't make much odds if we include it anyway there.

[benm (inactive), 2012/12/14 18:13:58]

Good point. I think the charset is considered a parameter to the MIME type, so
in all likelihood the underlying implementation will ignore it if it doesn't
make sense given the MIME type (seems chromium does this).

But I also agree it does seem a bit odd to append it when the embedder didn't
specify it and to do so given the MIME type wouldn't make much sense. I suppose
text/* is the only case that a charset does make sense so probably best to only
add it in that case.

         if (isBase64Encoded) {
             dataUrl.append(";base64");
         }
@@ -80,7 +98,7 @@ public class LoadUrlParams {
 
     /**
      * Helper method to create a LoadUrlParams object for data url with base
-     * and virtual url.
+     * and virtual url. Defaults to US-ASCII charset, as per RFC2397.
      * @param data Data to be loaded.
      * @param mimeType Mime type of the data.
      * @param isBase64Encoded True if the data is encoded in Base 64 format.
@@ -94,7 +112,28 @@ public class LoadUrlParams {
     public static LoadUrlParams createLoadDataParamsWithBaseUrl(
             String data, String mimeType, boolean isBase64Encoded,
             String baseUrl, String historyUrl) {
-        LoadUrlParams params = createLoadDataParams(data, mimeType, isBase64Encoded);
+        return createLoadDataParamsWithBaseUrl(data, mimeType, isBase64Encoded,
+                baseUrl, historyUrl, DATA_URL_DEFAULT_CHARSET);
+    }
+
+    /**
+     * Helper method to create a LoadUrlParams object for data url with base
+     * and virtual url.
+     * @param data Data to be loaded.
+     * @param mimeType Mime type of the data.
+     * @param isBase64Encoded True if the data is encoded in Base 64 format.
+     * @param baseUrl Base url of this data load. Note that for WebView compatibility,
+     *                baseUrl and historyUrl are ignored if this is a data: url.
+     *                Defaults to about:blank if null.
+     * @param historyUrl History url for this data load. Note that for WebView compatibility,
+     *                   this is ignored if baseUrl is a data: url. Defaults to about:blank
+     *                   if null.
+     * @param charset The character set for the data.
+     */
+    public static LoadUrlParams createLoadDataParamsWithBaseUrl(
+            String data, String mimeType, boolean isBase64Encoded,
+            String baseUrl, String historyUrl, String charset) {
+        LoadUrlParams params = createLoadDataParams(data, mimeType, isBase64Encoded, charset);
         // For WebView compatibility, when the base URL has the 'data:'
         // scheme, we treat it as a regular data URL load and skip setting
         // baseUrl and historyUrl.