Prevent guest views from issuing a search for empty text.

extensions/browser/api/guest_view/web_view/web_view_internal_api.cc

Index: extensions/browser/api/guest_view/web_view/web_view_internal_api.cc
diff --git a/extensions/browser/api/guest_view/web_view/web_view_internal_api.cc b/extensions/browser/api/guest_view/web_view/web_view_internal_api.cc
index cee2f5ea0b9c61505800981b0fec2a3909eb1101..0c1f7a0cc264fef8519619737cb5eb02d70066fd 100644
--- a/extensions/browser/api/guest_view/web_view/web_view_internal_api.cc
+++ b/extensions/browser/api/guest_view/web_view/web_view_internal_api.cc
@@ -45,10 +45,12 @@ const char kIndexedDBKey[] = "indexedDB";
 const char kLocalStorageKey[] = "localStorage";
 const char kWebSQLKey[] = "webSQL";
 const char kSinceKey[] = "since";
-const char kLoadFileError[] = "Failed to load file: \"*\". ";
-const char kViewInstanceIdError[] = "view_instance_id is missing.";
+
 const char kDuplicatedContentScriptNamesError[] =
     "The given content script name already exists.";
+const char kEmptyFindTextError[] = "Find called with no text";
+const char kLoadFileError[] = "Failed to load file: \"*\". ";
+const char kViewInstanceIdError[] = "view_instance_id is missing.";
 
 uint32 MaskForKey(const char* key) {
   if (strcmp(key, kAppCacheKey) == 0)
@@ -632,6 +634,11 @@ bool WebViewInternalFindFunction::RunAsyncSafe(WebViewGuest* guest) {
   base::string16 search_text;
   base::UTF8ToUTF16(
       params->search_text.c_str(), params->search_text.length(), &search_text);
+  if (search_text.empty()) {

[Fady Samuel, 2015/09/26 00:14:34]

I don't think this is the correct solution. I think this breaks the <webview>
Find API. I believe you can provide find with an empty string to "FindNext".
paulmeyer@ wrote this API. Passing this bug along to him.

[Lei Zhang, 2015/09/26 00:22:01]

You are referring to https://developer.chrome.com/apps/tags/webview#method-find
right?

What's the point of searching for no text? I guess the alternative is to just
immediately reply "successfully" with no results.

[Charlie Reis, 2015/09/28 19:35:17]

It does seem like a nonsensical case to me.  I'd be ok with either returning 0
results or an error, depending on what the <webview> folks want their API to do.

+    error_ = kEmptyFindTextError;
+    SendResponse(false);
+    return true;
+  }
 
   // Set the find options to their default values.
   blink::WebFindOptions options;