Add unit tests for page sharing, and check for sharing from private dir.

We should not be sharing files from our private directory, they are not
sharable, and could cause a crash.  This change marks the file as not
sharable (when the P2P sharing flag is turned on) so we avoid the crash.

To tell if the file is in a private directory, we add a new file to the
OfflinePageBridge to get the information from the C++ side.

Previously there were no unit tests for maybeShareOfflinePage().  This
change adds some unit tests for it as a basis for checking the sharing
restriction, then adds more tests for the sharing restriction.


Bug: 817611
Change-Id: Ic0361a6eaf2698562a4998c2e027081c76318bc5
Reviewed-on: https://chromium-review.googlesource.com/961542
Commit-Queue: Peter Williamson <petewil@chromium.org>
Reviewed-by: Jian Li <jianli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543851}

chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageBridge.java

@@ -646,6 +646,15 @@ public class OfflinePageBridge {
         return nativeIsOfflinePage(mNativeOfflinePageBridge, webContents);
     }
 
+    /**
+     * Checks if the supplied file path is in a private dir internal to chrome.
+     * @param file_path Path of the file to check.
+     * @return True if the file is in a private directory.
+     */
+    public boolean isInPrivateDirectory(String filePath) {
+        return nativeIsInPrivateDirectory(mNativeOfflinePageBridge, filePath);
+    }
+
     /**
      * Retrieves the offline page that is shown for the tab.
      * @param webContents Web contents used to find the offline page.
@@ -820,6 +829,8 @@ public class OfflinePageBridge {
             WebContents webContents, String nameSpace, String url, int uiAction, String origin);
     private native boolean nativeIsOfflinePage(
             long nativeOfflinePageBridge, WebContents webContents);
+    private native boolean nativeIsInPrivateDirectory(
+            long nativeOfflinePageBridge, String filePath);
     private native OfflinePageItem nativeGetOfflinePage(
             long nativeOfflinePageBridge, WebContents webContents);
     private native void nativeCheckForNewOfflineContent(

chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageUtils.java

@@ -367,17 +367,9 @@ public class OfflinePageUtils {
         }
 
         OfflinePageItem offlinePage = offlinePageBridge.getOfflinePage(tab.getWebContents());
-        // Bail if there is no offline page or sharing is not enabled.
-        if (offlinePage == null || !OfflinePageBridge.isPageSharingEnabled()) return false;
-
-        // If we share a page with a content URI, it will not have a file path.
-        // We cannot share it without a file path, so return false. That will give other
-        // sharing methods a chance to run.
         String offlinePath = offlinePage.getFilePath();
-        if (offlinePath.isEmpty()) {
-            Log.w(TAG, "Tried to share a page with no path.");
-            return false;
-        }
+
+        if (!isOfflinePageShareable(offlinePageBridge, offlinePage)) return false;
 
         final String tabTitle = tab.getTitle();
         final String tabUrl = tab.getUrl();
@@ -401,6 +393,31 @@ public class OfflinePageUtils {
         return true;
     }
 
+    /**
+     * Check to see if the offline page is sharable.
+     * @param offlinePage Page to check for sharability.
+     * @return true if this page can be shared.
+     */
+    public static boolean isOfflinePageShareable(
+            OfflinePageBridge offlinePageBridge, OfflinePageItem offlinePage) {
+        // Return false if there is no offline page or sharing is not enabled.
+        if (offlinePage == null || !OfflinePageBridge.isPageSharingEnabled()) return false;
+
+        // We cannot share a file without a file path, so return false.
+        // TODO(petewil) Allow sharing if there is a content or file URI, even if there is no path.
+        // https://crbug.com/817608
+        String offlinePath = offlinePage.getFilePath();
+        if (offlinePath.isEmpty()) {
+            Log.w(TAG, "Tried to share a page with no path.");
+            return false;
+        }
+
+        // If the page is not in a public location, we cannot share it.
+        if (offlinePageBridge.isInPrivateDirectory(offlinePath)) return false;
+
+        return true;
+    }
+
     /**
      * Retrieves the extra request header to reload the offline page.
      * @param tab The current tab.

chrome/browser/offline_pages/android/offline_page_bridge.cc

@@ -790,6 +790,14 @@ jboolean OfflinePageBridge::IsOfflinePage(
              web_contents) != nullptr;
 }
 
+jboolean OfflinePageBridge::IsInPrivateDirectory(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj,
+    const base::android::JavaParamRef<jstring>& j_file_path) {
+  base::FilePath file_path(ConvertJavaStringToUTF8(env, j_file_path));
+  return offline_page_model_->IsArchiveInInternalDir(file_path);
+}
+
 ScopedJavaLocalRef<jobject> OfflinePageBridge::GetOfflinePage(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj,

chrome/browser/offline_pages/android/offline_page_bridge.h

@@ -179,6 +179,11 @@ class OfflinePageBridge : public OfflinePageModel::Observer,
       const base::android::JavaParamRef<jobject>& obj,
       const base::android::JavaParamRef<jobject>& j_web_contents);
 
+  jboolean IsInPrivateDirectory(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jstring>& j_file_path);
+
   base::android::ScopedJavaLocalRef<jobject> GetOfflinePage(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj,