Selecting 'alt+left arrow' key in PDF does not move to previous url page. similarly 'alt+right arrow' key in PDF does not move to next url page.

Currently alt+arrow, ctrl+arrow,shift+arrow work like when
user select just arrow key, so with in the pdf file movement happen.
That is wrong.
It should be like:
1.Page should move up with in PDF when
 -Selecting Shift+Spacebar.
 -Selecting Pageup key.
 -Selecting only Left Arrow Key.
2.Page should move down with in PDF when
 -Selecting Spacebar.
 -Selecting Pagedown key.
 -Selecting only Right Arrow Key.

Changes added so that alt+ arrow key should have default behavior
that is moving to previous or next url.

BUG=75089

Review URL: https://codereview.chromium.org/802083002

Cr-Commit-Position: refs/heads/master@{#308511}

1 files changed, 5 insertions, 2 deletions

diff --git a/pdf/instance.cc b/pdf/instance.cc
index a8a71e8..8dc69be 100644
--- a/pdf/instance.cc
+++ b/pdf/instance.cc
@@ -532,8 +532,11 @@ bool Instance::HandleInputEvent(const pp::InputEvent& event) {
     pp::KeyboardInputEvent keyboard_event(event);
     bool no_h_scrollbar = !h_scrollbar_.get();
     uint32_t key_code = keyboard_event.GetKeyCode();
-    bool page_down = no_h_scrollbar && key_code == ui::VKEY_RIGHT;
-    bool page_up = no_h_scrollbar && key_code == ui::VKEY_LEFT;
+    bool has_modifiers = keyboard_event.GetModifiers() != 0;
+    bool page_down =
+        no_h_scrollbar && !has_modifiers && key_code == ui::VKEY_RIGHT;
+    bool page_up =
+        no_h_scrollbar && !has_modifiers && key_code == ui::VKEY_LEFT;
     if (zoom_mode_ == ZOOM_FIT_TO_PAGE) {
       bool has_shift =
           keyboard_event.GetModifiers() & PP_INPUTEVENT_MODIFIER_SHIFTKEY;