Steps to reproduce:
- Enable the API in Settings > Chromium > Experimental Settings > Web APIs > Enable Payment Request.
- Restart Chrome.
- Navigate to https://justindonnelly.github.io/pr/us/.
- Touch the "Buy" button.
- Browser crashes (relevant portion of the stack trace copied below).

rohitrao, do you know why the default favicon is not being provided by navigationItem->GetFavicon().image in this case? (See go/qfxrl) I can fix the crash by checking navigationItem->GetFavicon().image.IsEmpty() but this leaves me with nothing to show in the UI. I'd like to show the default, sheet-of-paper favicon as is done in the tab switcher.

The comment in favicon_status.h suggests that I should be getting the default favicon from the image property ("If the favicon has not been explicitly set or it empty, it will return the default favicon.") Is that comment just out-of-date? Do I need to load the default image explicitly as is done in tab_switcher_utils.mm?

------ Stack trace ------
[1206/103037.477048:FATAL:image.cc(741)] Check failed: storage_.get(). 
0   Chromium                            0x000000011096e27e _ZN4base5debug10StackTraceC2Ev + 30
1   Chromium                            0x000000011096e2e5 _ZN4base5debug10StackTraceC1Ev + 21
2   Chromium                            0x00000001109e1240 _ZN7logging10LogMessageD2Ev + 80
3   Chromium                            0x00000001109def35 _ZN7logging10LogMessageD1Ev + 21
4   Chromium                            0x000000011346a317 _ZNK3gfx5Image17GetRepresentationENS0_18RepresentationTypeEb + 199
5   Chromium                            0x000000011346ac9d _ZNK3gfx5Image9ToUIImageEv + 61
6   Chromium                            0x0000000110291d5f -[PaymentRequestManager handleRequestShow:] + 1247
7   Chromium                            0x0000000110291612 -[PaymentRequestManager handleScriptCommand:] + 1154
8   Chromium                            0x0000000110290e2c __46-[PaymentRequestManager enableCurrentWebState]_block_invoke + 124