Clean up PDF plugin dependencies.

pdf/pdf.gyp

 {
   'variables': {
     'chromium_code': 1,
     'pdf_enable_xfa%': 0,
     'pdf_engine%': 0,  # 0 PDFium
   },
   'targets': [
     {
       'target_name': 'pdf',
       'type': 'static_library',
       'dependencies': [
         '../base/base.gyp:base',
-        '../components/components.gyp:ui_zoom',
-        '../content/content.gyp:content_common',
         '../gin/gin.gyp:gin',
         '../net/net.gyp:net',
         '../ppapi/ppapi.gyp:ppapi_cpp_objects',
         '../ppapi/ppapi.gyp:ppapi_internal_module',
-        '../third_party/pdfium/pdfium.gyp:pdfium',
       ],
       'ldflags': [ '-L<(PRODUCT_DIR)',],
       'sources': [
         'chunk_stream.h',
         'chunk_stream.cc',
         'document_loader.h',
         'document_loader.cc',
         'draw_utils.cc',
         'draw_utils.h',
         'out_of_process_instance.cc',
         'out_of_process_instance.h',
         'paint_aggregator.cc',
         'paint_aggregator.h',
         'paint_manager.cc',
         'paint_manager.h',
         'pdf.cc',
         'pdf.h',
         'pdf_engine.h',
         'preview_mode_client.cc',
         'preview_mode_client.h',
       ],
       'conditions': [
         ['pdf_engine==0', {
+          'dependencies': [
+            '../third_party/pdfium/pdfium.gyp:pdfium',
+          ],
           'sources': [
             'pdfium/pdfium_api_string_buffer_adapter.cc',
             'pdfium/pdfium_api_string_buffer_adapter.h',
             'pdfium/pdfium_assert_matching_enums.cc',
             'pdfium/pdfium_engine.cc',
             'pdfium/pdfium_engine.h',
             'pdfium/pdfium_mem_buffer_file_read.cc',
             'pdfium/pdfium_mem_buffer_file_read.h',
             'pdfium/pdfium_mem_buffer_file_write.cc',
             'pdfium/pdfium_mem_buffer_file_write.h',
             'pdfium/pdfium_page.cc',
             'pdfium/pdfium_page.h',
             'pdfium/pdfium_range.cc',
             'pdfium/pdfium_range.h',
           ],
         }],
         ['pdf_enable_xfa==1', {
            'defines': [
              'PDF_ENABLE_XFA',
            ]
         }],
         ['OS=="win"', {
           # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
           'msvs_disabled_warnings': [ 4267, ],
         }],
       ],
     },
   ],
 }