Hotfix: hasText value is incorrectly set

Following the refactoring in CL: 2694543002 the value of hasText is incorrectly
set. To be precise, hasText is always set to the negate of its correct value.

BUG=602427

Review-Url: https://codereview.chromium.org/2735633005
Cr-Commit-Position: refs/heads/master@{#454901}
(cherry picked from commit 6e3e9e5)

Review-Url: https://codereview.chromium.org/2741503002 .
Cr-Commit-Position: refs/branch-heads/3029@{#66}
Cr-Branched-From: 939b32e-refs/heads/master@{#454471}

content/browser/renderer_host/render_widget_host_view_mac.mm

@@ -3422,7 +3422,7 @@ - (id)validRequestorForSendType:(NSString*)sendType
   BOOL returnTypeIsString = [returnType isEqual:NSStringPboardType];
   const content::TextInputManager::TextSelection* selection =
       renderWidgetHostView_->GetTextSelection();
-  BOOL hasText = !selection || selection->selected_text().empty();
+  BOOL hasText = selection && !selection->selected_text().empty();
   BOOL takesText =
       renderWidgetHostView_->GetTextInputType() != ui::TEXT_INPUT_TYPE_NONE;