[TextBlob] Fall back to TightRunBounds when the font bounds are empty
[TextBlob] Fall back to TightRunBounds when the font bounds are empty

Empty font bounds are likely an indication of a font bug.  As a best
effort, we can use TightRunBounds in this easily detectable case.

BUG=507022
R=reed@google.com,bungeman@google.com

Review URL: https://codereview.chromium.org/1284693002

tmpvar/skia.cc,qrealka/skia-hc,aosp-mirror/platform_external_skia,vanish87/skia,vanish87/skia,tmpvar/skia.cc,shahrzadmn/skia,tmpvar/skia.cc,tmpvar/skia.cc,nvoron23/skia,google/skia,vanish87/skia,ominux/skia,vanish87/skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,vanish87/skia,vanish87/skia,tmpvar/skia.cc,HalCanary/skia-hc,ominux/skia,google/skia,qrealka/skia-hc,qrealka/skia-hc,aosp-mirror/platform_external_skia,google/skia,vanish87/skia,rubenvb/skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,shahrzadmn/skia,aosp-mirror/platform_external_skia,google/skia,tmpvar/skia.cc,ominux/skia,vanish87/skia,shahrzadmn/skia,HalCanary/skia-hc,ominux/skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,ominux/skia,Hikari-no-Tenshi/android_external_skia,tmpvar/skia.cc,shahrzadmn/skia,rubenvb/skia,HalCanary/skia-hc,google/skia,aosp-mirror/platform_external_skia,shahrzadmn/skia,google/skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,ominux/skia,google/skia,vanish87/skia,ominux/skia,google/skia,google/skia,tmpvar/skia.cc,shahrzadmn/skia,rubenvb/skia,shahrzadmn/skia,nvoron23/skia,rubenvb/skia,qrealka/skia-hc,aosp-mirror/platform_external_skia,nvoron23/skia,ominux/skia,nvoron23/skia,rubenvb/skia,rubenvb/skia,tmpvar/skia.cc,qrealka/skia-hc,rubenvb/skia,nvoron23/skia,nvoron23/skia,rubenvb/skia,ominux/skia,rubenvb/skia,aosp-mirror/platform_external_skia,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,qrealka/skia-hc,shahrzadmn/skia,nvoron23/skia,google/skia,nvoron23/skia,qrealka/skia-hc,shahrzadmn/skia,aosp-mirror/platform_external_skia,qrealka/skia-hc,nvoron23/skia,HalCanary/skia-hc