Material PDF: Add tooltips to all the viewer toolbar buttons

Disabling presubmit as it complains about the parameters for
paper-tooltip.

BUG=489715
NOPRESUBMIT=true

Review URL: https://codereview.chromium.org/1360513003

Cr-Commit-Position: refs/heads/master@{#350305}
diff --git a/components/pdf_strings.grdp b/components/pdf_strings.grdp
index 7a83909..f06125aa 100644
--- a/components/pdf_strings.grdp
+++ b/components/pdf_strings.grdp
@@ -4,14 +4,47 @@
     <message name="IDS_PDF_NEED_PASSWORD" desc="A message asking the user for a password to open a PDF file.">
       This document is password protected.  Please enter a password.
     </message>
+    <message name="IDS_PDF_PASSWORD_SUBMIT" desc="Button label for the buton to submit the PDF password form">
+      Submit
+    </message>
+
     <message name="IDS_PDF_PAGE_LOADING" desc="A message displayed on the PDF page while page is loading.">
       Loading...
     </message>
     <message name="IDS_PDF_PAGE_LOAD_FAILED" desc="A message displayed on the PDF control to indicate that the PDF document failed to load.">
       Failed to load PDF document
     </message>
-    <message name="IDS_PDF_PROGRESS_LOADING" desc="A message displayed on the progress control over PDF page during document loading.">
-      Loading
+    <message name="IDS_PDF_PAGE_RELOAD_BUTTON" desc="Button label for the button to reload a PDF which has failed to load">
+      Reload
+    </message>
+
+    <message name="IDS_PDF_BOOKMARKS" desc="Label for the bookmarks (table of contents) of a PDF document. Used as a heading for the bookmarks menu, and as a tooltip to open that menu">
+      Bookmarks
+    </message>
+
+    <message name="IDS_PDF_TOOLTIP_ROTATE_CW" desc="Button tooltip for the button which rotates a PDF document clockwise">
+      Rotate clockwise
+    </message>
+    <message name="IDS_PDF_TOOLTIP_ROTATE_CCW" desc="Button tooltip for the button which rotates a PDF document counterclockwise">
+      Rotate counterclockwise
+    </message>
+    <message name="IDS_PDF_TOOLTIP_SAVE" desc="Button tooltip for the button to save a PDF document">
+      Save
+    </message>
+    <message name="IDS_PDF_TOOLTIP_PRINT" desc="Button tooltip for the button to print a PDF document">
+      Print
+    </message>
+    <message name="IDS_PDF_TOOLTIP_FIT_PAGE" desc="Button tooltip for the button which zooms a PDF so that a single page is visible on screen">
+      Fit to page
+    </message>
+    <message name="IDS_PDF_TOOLTIP_FIT_WIDTH" desc="Button tooltip for the button which zooms a PDF so that the width of a single page fills the window horizontally">
+      Fit to width
+    </message>
+    <message name="IDS_PDF_TOOLTIP_ZOOM_IN" desc="Button tooltip for the button which zooms in a PDF, so that the document appears larger">
+      Zoom in
+    </message>
+    <message name="IDS_PDF_TOOLTIP_ZOOM_OUT" desc="Button tooltip for the button which zooms out a PDF, so that the document appears smaller">
+      Zoom out
     </message>
   </if>
 </grit-part>