Reproduction steps:
1. Open the attached project "WebGL-MemoryTest-main.zip"
2. In the Project window under "Assets/Scenes" open "MemoryTest.unity" and switch to WebGL Platform
3. Build for WebGL
4. Use https://app.netlify.com for hosting the WebGL Build
5. Enter the address generated by https://app.netlify.com in the Android device
6. Navigate to "edge://inspect/#devices" or "chrome://inspect/#devices"
7. Attach Chrome/Edge DevTools to the device
8. In the Input Field enter "200" and press the "Add Textures" Button
9. Inspect the DevTools Console

Expected result: Memory growth above 256 Mb does not cause [Could Not Allocate] memory errors in Chromium based browsers
Actual result: Memory growth above 256 Mb causes [Could Not Allocate] memory errors in Chromium based browsers

Reproduced on these devices:
N/A, Samsung Galaxy S9 (SM-G960F), Android 8.0.0, CPU: Exynos 9 Series 9810, GPU: Mali-G72
VLNQA00339, Lge LG V50 ThinQ 5G (LM-V500N), Android 10, CPU: Snapdragon 855 SM8150, GPU: Adreno (TM) 640
VLNQA00316, Samsung Galaxy Note10 (SM-N970F), Android 9, CPU: Exynos 9 Series 9825, GPU: Mali-G76

Reproduces on: 2019.4.17f1, 2020.2.1f1, 2021.1.0b1, 2021.2.0a1
Could not test on 2018.4.30f1 due to the project breaking when downgrading

Tested with these browsers on Android: Chrome (87.0.4280.101), Ecosia (4.1.3.240), Opera (61.2.3076.56749)

Notes:
-Issue does not reproduce on Dekstop browsers
-Issue does not reproduce on Android Firefox
-You can set the initial memory to a higher value such as 512mb, but increasing memory above that still causes the browser to fail when allocating memory.