Disable exceptions for the pdfium targets, now that pdfium:29 is done.

pdfium.gyp

Index: pdfium.gyp
diff --git a/pdfium.gyp b/pdfium.gyp
index 277c1c74a080523330ced15628c5e5f7074d66cd..5c5b9ca0b0b0c7a64faf7d42b5c50b0c65e34fe7 100644
--- a/pdfium.gyp
+++ b/pdfium.gyp
@@ -13,18 +13,7 @@
       ['pdf_use_skia==1', {
         'defines': ['_SKIA_SUPPORT_'],
       }],
-      # pdfium uses exceptions. Override the default exceptions-off setting
-      # from chromium.
-      # TODO: Instead, change pdfium to not use exceptions, and remove this.
-      ['OS=="mac"', {
-        'xcode_settings': { 'GCC_ENABLE_CPP_EXCEPTIONS': 'YES', },
-      }],
-      ['OS=="win"', {
-        'msvs_settings': { 'VCCLCompilerTool': { 'ExceptionHandling': '1', }, },
-        'defines!': [ '_HAS_EXCEPTIONS=0', ],
-      }],
       ['OS=="linux"', {
-        'cflags!': [ '-fno-exceptions', ],
         'conditions': [
           ['target_arch=="x64"', {
             'defines' : [ '_FX_CPU_=_FX_X64_', ],