Handle ctrl + shift + left click on links in PDF.

pdf/pdfium/pdfium_engine.cc

Index: pdf/pdfium/pdfium_engine.cc
diff --git a/pdf/pdfium/pdfium_engine.cc b/pdf/pdfium/pdfium_engine.cc
index d0796a5e4eca0a9a2515f452110d92f5ecea0aad..5f198a4affb5f6431e5b971ab4adac2472f88b84 100644
--- a/pdf/pdfium/pdfium_engine.cc
+++ b/pdf/pdfium/pdfium_engine.cc
@@ -1645,7 +1645,26 @@ bool PDFiumEngine::OnMouseUp(const pp::MouseInputEvent& event) {
     if (area == PDFiumPage::WEBLINK_AREA) {
       bool open_in_new_tab = !!(event.GetModifiers() & kDefaultKeyModifier) ||
           !!(event.GetModifiers() & PP_INPUTEVENT_MODIFIER_MIDDLEBUTTONDOWN);
-      client_->NavigateTo(target.url, open_in_new_tab);
+
+      bool shift = !!(event.GetModifiers() & PP_INPUTEVENT_MODIFIER_SHIFTKEY);
+
+      PDFEngine::Client::NavigateOption option;
+      if (open_in_new_tab) {
+        if (shift) {
+          option =
+              PDFEngine::Client::NavigateOption::OPEN_IN_NEW_FOREGROUND_TAB;
+        } else {
+          option =
+              PDFEngine::Client::NavigateOption::OPEN_IN_NEW_BACKGROUND_TAB;
+        }
+      } else {
+        if (shift)
+          option = PDFEngine::Client::NavigateOption::OPEN_IN_NEW_WINDOW;
+        else
+          option = PDFEngine::Client::NavigateOption::OPEN_IN_CURRENT_TAB;
+      }
+
+      client_->NavigateTo(target.url, option);
       client_->FormTextFieldFocusChange(false);
       return true;
     }
@@ -3524,7 +3543,9 @@ void PDFiumEngine::Form_SetTextFieldFocus(FPDF_FORMFILLINFO* param,
 void PDFiumEngine::Form_DoURIAction(FPDF_FORMFILLINFO* param,
                                     FPDF_BYTESTRING uri) {
   PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
-  engine->client_->NavigateTo(std::string(uri), false);
+  engine->client_->NavigateTo(
+      std::string(uri),
+      PDFEngine::Client::NavigateOption::OPEN_IN_CURRENT_TAB);
 }
 
 void PDFiumEngine::Form_DoGoToAction(FPDF_FORMFILLINFO* param,