tree 9cc6b44a5c498e7b4c0ddf3dddb4a30654852ea5
parent f3c5fc09f0818ec378890ade42bef40eebd3f0a9
author npm <npm@chromium.org> 1476812300 -0700
committer Commit bot <commit-bot@chromium.org> 1476812300 -0700

Traverse PDF page tree only once in CPDF_Document

In our current implementation of CPDF_Document::GetPage, we traverse
the PDF page tree until we find the index we are looking for. This is
slow when we do calls GetPage(0), GetPage(1), ... since in this case
the page tree will be traversed n times if there are n pages. This CL
makes sure the page tree is only traversed once.

Time to load the PDF from the bug below in chrome official build:
Before this CL: 1 minute 40 seconds
After this CL: 5 seconds

BUG=chromium:638513

Review-Url: https://codereview.chromium.org/2414423002