Reproducible on ToT.
I didn't verify reproducibility on branches. I don't experience a crash with current appstore version. Please triage accordingly.

Steps to repro:
1. Open amazon.com
2. Select the "deals" page
3. Scroll to the bottom of the page
4. In the search box in the bottom, type any text, for example, "Google"
5. Hit enter

Expected result:
You navigate to a page 

Actual result:
 DCHECK(_documentURL == _lastRegisteredRequestURL ||  // latest navigation
         !isLastNavigation ||                          // previous navigation
         (!_lastRegisteredRequestURL.is_valid() &&     // invalid URL load
          _documentURL.spec() == url::kAboutBlankURL));

Values I observe:

_documentURL = https://www.amazon.com/gp/aw/s/ref=is_s?k=Google
_lastRegisteredRequestURL = https://www.amazon.com/gp/aw/gb?pf_rd_p=9323e93c-7abe-488f-aeb4-8ba014079068&pf_rd_s=grid-unrec-2&pf_rd_t=Gateway&pf_rd_i=mobile&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=81P9ET6F5XHQ639FJT4B&pf_rd_r=81P9ET6F5XHQ639FJT4B&pf_rd_p=9323e93c-7abe-488f-aeb4-8ba014079068&ref_=gwm_dotd_s&nocache=1493815786571
_lastRegisteredRequestURL.is_valid() = true
_documentURL.spec() = https://www.amazon.com/gp/aw/s/ref=is_s?k=Google
isLastNavigation = YES