DCHECK that jstring to C++ string conversions don't pass in null.

chrome/android/java/src/org/chromium/chrome/browser/contextmenu/ContextMenuHelper.java

Index: chrome/android/java/src/org/chromium/chrome/browser/contextmenu/ContextMenuHelper.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/contextmenu/ContextMenuHelper.java b/chrome/android/java/src/org/chromium/chrome/browser/contextmenu/ContextMenuHelper.java
index 5640a2d473bf3fdc8c91ad011faa5370a63e92ed..ac5f96deea5ad4c38f75ea47857dbe79eed3f083 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/contextmenu/ContextMenuHelper.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/contextmenu/ContextMenuHelper.java
@@ -25,9 +25,6 @@ import org.chromium.ui.base.WindowAndroid;
  * A helper class that handles generating context menus for {@link ContentViewCore}s.
  */
 public class ContextMenuHelper implements OnCreateContextMenuListener, OnMenuItemClickListener {
-    private static final String DATA_REDUCTION_PROXY_PASSTHROUGH_HEADER =
-            "Chrome-Proxy: pass-through\r\n";
-
     private long mNativeContextMenuHelper;
 
     private ContextMenuPopulator mPopulator;
@@ -92,8 +89,7 @@ public class ContextMenuHelper implements OnCreateContextMenuListener, OnMenuIte
      */
     public void startContextMenuDownload(boolean isLink, boolean isDataReductionProxyEnabled) {
         if (mNativeContextMenuHelper != 0) {
-            nativeOnStartDownload(mNativeContextMenuHelper, isLink,
-                    isDataReductionProxyEnabled ? DATA_REDUCTION_PROXY_PASSTHROUGH_HEADER : null);
+            nativeOnStartDownload(mNativeContextMenuHelper, isLink, isDataReductionProxyEnabled);
         }
     }
 
@@ -152,7 +148,7 @@ public class ContextMenuHelper implements OnCreateContextMenuListener, OnMenuIte
     }
 
     private native void nativeOnStartDownload(
-            long nativeContextMenuHelper, boolean isLink, String headers);
+            long nativeContextMenuHelper, boolean isLink, boolean isDataReductionProxyEnabled);
     private native void nativeSearchForImage(long nativeContextMenuHelper);
     private native void nativeShareImage(long nativeContextMenuHelper);
 }