UI changes associated with downloads resumption.

content/browser/download/download_item_impl.cc

Index: content/browser/download/download_item_impl.cc
diff --git a/content/browser/download/download_item_impl.cc b/content/browser/download/download_item_impl.cc
index df138ced42329afa18844736a20a48b9f07602bb..4ba68aca43604c00efb6d3425a3b3736ec925488 100644
--- a/content/browser/download/download_item_impl.cc
+++ b/content/browser/download/download_item_impl.cc
@@ -478,6 +478,10 @@ bool DownloadItemImpl::IsPaused() const {
   return is_paused_;
 }
 
+bool DownloadItemImpl::CanResumeInterrupted() const {
+  return GetResumeMode() != RESUME_MODE_INVALID;
+}
+
 bool DownloadItemImpl::IsTemporary() const {
   return is_temporary_;
 }
@@ -686,6 +690,22 @@ bool DownloadItemImpl::CanOpenDownload() {
       !file_externally_removed_;
 }
 
+bool DownloadItemImpl::CanResumeDownload() const {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  // Do not allow interrupted downloads to be resumed until the target name
+  // has been determined, and the user has validated any dangerous items.
+  // TODO(rdsmith) -- Add a state indicating that filename determination has
+  // occurred.
+  if (GetTargetFilePath().empty())
+    return false;
+
+  if (GetSafetyState() == DANGEROUS)
+    return false;
+
+  return IsInProgress() || (GetResumeMode() != RESUME_MODE_INVALID);
+}
+
 bool DownloadItemImpl::ShouldOpenFileBasedOnExtension() {
   return delegate_->ShouldOpenFileBasedOnExtension(GetUserVerifiedFilePath());
 }